fix(tests): update unconverter and add concurrency in debug output

Bumps [golang.org/x/net](https://github.com/golang/net) from 0.49.0 to 0.50.0.
- [Commits](https://github.com/golang/net/compare/v0.49.0...v0.50.0)

---
updated-dependencies:
- dependency-name: golang.org/x/net
  dependency-version: 0.50.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/continuous-integration.yml

@@ -31,7 +31,7 @@ jobs:
       - name: Run linters
         uses: golangci/golangci-lint-action@v9
         with:
-          version: v2.5.0
+          version: v2.10.1
 
   lint-prettier:
     name: Lint non-Golang codebase

AGENTS.md

@@ -0,0 +1,66 @@
+# Operational Guidelines for Gotenberg
+
+As an AI agent working on the Gotenberg repository, you are expected to act with the diligence and architectural foresight of a Senior Go Engineer. Gotenberg is a widely used production dependency; stability and backward compatibility are paramount.
+
+## 1. Core Philosophy & Stability
+
+- **Backward Compatibility is Law:** This project creates a public API. Never modify existing flags, configuration environment variables, or API form fields unless explicitly instructed to perform a breaking change. If a change is breaking, it must be flagged immediately in the plan.
+- **Defensive Programming:** Assume input data is malformed. Handle errors explicitly. Do not panic.
+- **Atomic Commits:** Isolate refactoring from feature additions. A Pull Request should do one thing well.
+
+## 2. Development Workflow & Tooling
+
+You must rely strictly on the project's Makefile for build and verification tasks. Do not run `go` commands directly unless debugging a specific package requires it.
+
+- **Formatting:** Run `make fmt` to format Go code before committing.
+- **Linting:**
+  - Run `make lint` to ensure Go code strictly adheres to the `.golangci.yml` configuration.
+  - Run `make lint-prettier` to verify formatting for non-Go files (Markdown, YAML, etc.).
+  - Zero linting errors are permitted.
+- **Building:** Run `make build` to verify compilation and Docker image construction.
+
+## 3. Architecture & Code Structure
+
+- **Idiomatic Go:** Follow "Effective Go" principles.
+- **Directory Separation:**
+  - `cmd/`: Application entry points only. Contains wiring and startup logic. **No business logic is permitted here.**
+  - `pkg/`: Core library code and modules. All business logic resides here.
+- **Module System:** Gotenberg is modular (e.g., Chromium, LibreOffice). When adding features, determine if they belong to an existing module or require a new strict isolation.
+
+## 4. Testing Standards
+
+Gotenberg utilizes a split testing strategy. **Integration tests are the primary and preferred method for verifying features.**
+
+- **Integration Tests (`make test-integration`):**
+  - **First Priority:** Always start here when adding features or routes.
+  - Gotenberg uses **Gherkin (Godog)** for end-to-end verification.
+  - You **must** create or update the corresponding `.feature` file in `test/integration`.
+  - These tests run within the Docker context; ensure environment consistency.
+- **Unit Tests (`make test-unit`):**
+  - Use table-driven tests for pure logic within `pkg/`.
+  - Mock external dependencies (filesystem, network) where appropriate.
+
+## 5. Documentation Requirements
+
+- **No README Updates:** Do not modify the root `README.md` unless explicitly asked.
+- **GoDoc is Mandatory:**
+  - **New Packages:** If creating a new package, you must include a `doc.go` file containing the package-level documentation.
+  - **Exported Symbols:** Every exported function, type, constant, and variable must have a proper GoDoc comment starting with its name.
+  - **Quality:** Comments must be complete sentences explaining _what_ the symbol does and _how_ to use it.
+  - **Example:**
+    ```go
+    // Convert transforms the input document to PDF using the Chromium engine.
+    // It returns an error if the connection to the browser instance fails.
+    func Convert(...) error
+    ```
+
+## 6. Definition of Done
+
+A task is considered complete only when:
+
+1.  The code compiles via `make build`.
+2.  The code is formatted via `make fmt`.
+3.  All linters pass via `make lint` and `make lint-prettier`.
+4.  Integration scenarios pass via `make test-integration`.
+5.  Unit tests pass via `make test-unit`.
+6.  All exported symbols and new packages have compliant GoDoc.

Makefile

@@ -10,6 +10,7 @@ build: ## Build the Gotenberg's Docker image
 	-t $(DOCKER_REGISTRY)/$(DOCKER_REPOSITORY):$(GOTENBERG_VERSION) \
 	-f $(DOCKERFILE) $(DOCKER_BUILD_CONTEXT)
 
+TZ=UTC
 GOTENBERG_HIDE_BANNER=false
 GOTENBERG_GRACEFUL_SHUTDOWN_DURATION=30s
 GOTENBERG_BUILD_DEBUG_DATA=true
@@ -30,8 +31,9 @@ API-DOWNLOAD-FROM-FROM-MAX-RETRY=4
 API-DISABLE-DOWNLOAD-FROM=false
 API_DISABLE_HEALTH_CHECK_LOGGING=false
 API_ENABLE_DEBUG_ROUTE=false
-CHROMIUM_RESTART_AFTER=10
+CHROMIUM_RESTART_AFTER=100
 CHROMIUM_MAX_QUEUE_SIZE=0
+CHROMIUM_MAX_CONCURRENCY=6
 CHROMIUM_AUTO_START=false
 CHROMIUM_START_TIMEOUT=20s
 CHROMIUM_ALLOW_INSECURE_LOCALHOST=false
@@ -86,6 +88,7 @@ run: ## Start a Gotenberg container
 	-p $(API_PORT):$(API_PORT) \
 	-e GOTENBERG_API_BASIC_AUTH_USERNAME=$(GOTENBERG_API_BASIC_AUTH_USERNAME) \
 	-e GOTENBERG_API_BASIC_AUTH_PASSWORD=$(GOTENBERG_API_BASIC_AUTH_PASSWORD) \
+	-e TZ=$(TZ) \
 	$(DOCKER_REGISTRY)/$(DOCKER_REPOSITORY):$(GOTENBERG_VERSION) \
 	gotenberg \
 	--gotenberg-hide-banner=$(GOTENBERG_HIDE_BANNER) \
@@ -109,6 +112,7 @@ run: ## Start a Gotenberg container
 	--chromium-restart-after=$(CHROMIUM_RESTART_AFTER) \
 	--chromium-auto-start=$(CHROMIUM_AUTO_START) \
 	--chromium-max-queue-size=$(CHROMIUM_MAX_QUEUE_SIZE) \
+	--chromium-max-concurrency=$(CHROMIUM_MAX_CONCURRENCY) \
 	--chromium-start-timeout=$(CHROMIUM_START_TIMEOUT) \
 	--chromium-allow-insecure-localhost=$(CHROMIUM_ALLOW_INSECURE_LOCALHOST) \
 	--chromium-ignore-certificate-errors=$(CHROMIUM_IGNORE_CERTIFICATE_ERRORS) \
@@ -164,6 +168,7 @@ PLATFORM=
 NO_CONCURRENCY=false
 # Available tags:
 # chromium
+# chromium-concurrent
 # chromium-convert-html
 # chromium-convert-markdown
 # chromium-convert-url
@@ -216,6 +221,7 @@ lint-todo: ## Find TODOs in Golang codebase
 
 .PHONY: fmt
 fmt: ## Format Golang codebase and "optimize" the dependencies
+	go fix ./...
 	golangci-lint fmt
 	go mod tidy
 

README.md

@@ -4,60 +4,46 @@
     <p align="center">A containerized API for seamless PDF conversion</p>
     <p align="center">
         <a href="https://hub.docker.com/r/gotenberg/gotenberg"><img alt="Total downloads (gotenberg/gotenberg)" src="https://img.shields.io/docker/pulls/gotenberg/gotenberg"></a>
-        <a href="https://hub.docker.com/r/thecodingmachine/gotenberg"><img alt="Total downloads (thecodingmachine/gotenberg)" src="https://img.shields.io/docker/pulls/thecodingmachine/gotenberg"></a>
         <a href="https://github.com/gotenberg/gotenberg/actions/workflows/continuous-integration.yml"><img alt="Continuous Integration" src="https://github.com/gotenberg/gotenberg/actions/workflows/continuous-integration.yml/badge.svg"></a>
         <a href="https://pkg.go.dev/github.com/gotenberg/gotenberg/v8"><img alt="Go Reference" src="https://pkg.go.dev/badge/github.com/gotenberg/gotenberg.svg"></a>
     </p>
     <p align="center">
         <a href="https://trendshift.io/repositories/2996"><img src="https://trendshift.io/api/badge/repositories/2996" alt="gotenberg%2Fgotenberg | Trendshift" style="width: 250px; height: 55px;" width="250" height="55"/></a>
     </p>
-    <p align="center"><a href="https://gotenberg.dev/docs/getting-started/introduction">Documentation</a> &#183; <a href="https://gotenberg.dev/docs/getting-started/installation#live-demo-">Live Demo</a> 🔥</p>
+    <p align="center"><a href="https://gotenberg.dev/docs/getting-started/introduction">Read the Documentation</a> &#183; <a href="https://gotenberg.dev/docs/getting-started/installation#live-demo-">Try the Live Demo</a> 🔥</p>
 </p>
 
 ---
 
-**Gotenberg** provides a developer-friendly API to interact with powerful tools like Chromium and LibreOffice for converting
+**Gotenberg** is a containerized API that abstracts the complexity of PDF conversion.
-numerous document formats (HTML, Markdown, Word, Excel, etc.) into PDF files, and more!
+
+It provides a `multipart/form-data` interface for interacting with powerful engines like Chromium and LibreOffice.
+Instead of managing heavy dependencies, browser versions, or fonts in your own backend, simply send your files to
+Gotenberg and get a PDF in return.
 
 ## Quick Start
 
 Open a terminal and run the following command:
 
-```
+```bash
 docker run --rm -p 3000:3000 gotenberg/gotenberg:8
 ```
 
-Alternatively, using the historic Docker repository from our sponsor [TheCodingMachine](https://www.thecodingmachine.com):
+With the API running at `http://localhost:3000`, you are now ready to head
-
+to the **[Full Documentation](https://gotenberg.dev/docs/getting-started/introduction)** to discover how to convert URLs,
-```
+local files, inject custom CSS, merge PDFs, and more.
-docker run --rm -p 3000:3000 thecodingmachine/gotenberg:8
-```
-
-The API is now available on your host at http://localhost:3000.
-
-Head to the [documentation](https://gotenberg.dev/docs/getting-started/introduction) to learn how to interact with it 🚀
 
 ## Sponsors
 
-<p align="center">
+Open-source development takes a significant amount of time, energy, and dedication. If Gotenberg helps streamline your
-    <a href="https://thecodingmachine.com">
+workflow or powers your business, please consider supporting its continuous improvement by [**becoming a sponsor**](https://github.com/sponsors/gulien)! ❤️
-        <img src="https://user-images.githubusercontent.com/8983173/130324668-9d6e7b35-53a3-49c7-a574-38190d2bd6b0.png" alt="TheCodingMachine Logo" width="333" height="163" />
-    </a>
-    <a href="https://pdfme.com?utm_source=gotenberg_github&utm_medium=website" target="_blank">
-        <img src="https://github.com/user-attachments/assets/2a75dd40-ca18-4d34-acd5-5dd474595168" alt="pdfme Logo" width="333" height="163" />
-    </a>
-</p>
 
-Sponsorships help maintain and improve Gotenberg - [become a sponsor](https://github.com/sponsors/gulien) ❤️
+**GitHub Sponsors**
 
----
+- [TheCodingMachine](https://thecodingmachine.com/)
+- [pdfme](https://pdfme.com/)
 
-<p align="center">
+**Powered By**
-  <strong>Powered by</strong>
-</p>
 
-<p align="center">
+- [Docker](https://docs.docker.com/docker-hub/repos/manage/trusted-content/dsos-program/)
-  <a href="https://jb.gg/OpenSource">
+- [JetBrains](https://www.jetbrains.com/community/opensource/)
-    <img src="https://resources.jetbrains.com/storage/products/company/brand/logos/jetbrains.svg" alt="JetBrains logo" width="200"/>
-  </a>
-</p>

build/Dockerfile

@@ -1,7 +1,7 @@
 # ARG instructions do not create additional layers. Instead, next layers will
 # concatenate them. Also, we have to repeat ARG instructions in each build
 # stage that uses them.
-ARG GOLANG_VERSION=1.25.5
+ARG GOLANG_VERSION=1.26.0
 
 # ----------------------------------------------
 # pdfcpu binary build stage
@@ -79,6 +79,9 @@ RUN jlink \
 # ----------------------------------------------
 FROM debian:13-slim AS base-image-stage
 
+ARG TIMEZONE=UTC
+ENV TZ=$TIMEZONE
+
 COPY --from=custom-jre-stage /custom-jre /opt/java
 
 ENV PATH="/opt/java/bin:${PATH}"
@@ -212,7 +215,7 @@ RUN \
     apt-get update -qq &&\
     apt-get upgrade -yqq &&\
     DEBIAN_FRONTEND=noninteractive apt-get install -y -qq --no-install-recommends -t trixie-backports libreoffice &&\
-    curl -Ls https://raw.githubusercontent.com/gotenberg/unoconverter/v0.1.1/unoconv -o /usr/bin/unoconverter &&\
+    curl -Ls https://raw.githubusercontent.com/gotenberg/unoconverter/v0.2.0/unoconv -o /usr/bin/unoconverter &&\
     chmod +x /usr/bin/unoconverter &&\
     # unoconverter will look for the Python binary, which has to be at version 3.
     ln -s /usr/bin/python3 /usr/bin/python &&\

cmd/gotenberg.go

@@ -45,10 +45,10 @@ func Run() {
 	fs.Bool("gotenberg-build-debug-data", true, "Set if build data is needed")
 
 	descriptors := gotenberg.GetModuleDescriptors()
-	var modsInfo string
+	var modsInfo strings.Builder
 	for _, desc := range descriptors {
 		fs.AddFlagSet(desc.FlagSet)
-		modsInfo += desc.ID + " "
+		modsInfo.WriteString(desc.ID + " ")
 	}
 
 	// Parse the flags.
@@ -94,7 +94,7 @@ func Run() {
 	if !hideBanner {
 		fmt.Printf(banner, Version)
 	}
-	fmt.Printf("[SYSTEM] modules: %s\n", modsInfo)
+	fmt.Printf("[SYSTEM] modules: %s\n", modsInfo.String())
 
 	ctx := gotenberg.NewContext(parsedFlags, descriptors)
 

go.mod

@@ -1,6 +1,6 @@
 module github.com/gotenberg/gotenberg/v8
 
-go 1.25.5
+go 1.26.0
 
 require (
 	github.com/alexliesenfeld/health v0.8.1
@@ -11,7 +11,7 @@ require (
 	github.com/dlclark/regexp2 v1.11.5
 	github.com/docker/docker v28.5.2+incompatible
 	github.com/docker/go-connections v0.6.0
-	github.com/gomarkdown/markdown v0.0.0-20250810172220-2e2c11897d1a
+	github.com/gomarkdown/markdown v0.0.0-20260217112301-37c66b85d6ab
 	github.com/google/uuid v1.6.0
 	github.com/hashicorp/go-retryablehttp v0.7.8
 	github.com/labstack/echo/v4 v4.15.0
@@ -19,15 +19,15 @@ require (
 	github.com/mholt/archives v0.1.5
 	github.com/microcosm-cc/bluemonday v1.0.27
 	github.com/prometheus/client_golang v1.23.2
-	github.com/shirou/gopsutil/v4 v4.25.12
+	github.com/shirou/gopsutil/v4 v4.26.1
 	github.com/spf13/pflag v1.0.10
 	github.com/testcontainers/testcontainers-go v0.40.0
 	go.uber.org/multierr v1.11.0
 	go.uber.org/zap v1.27.1
-	golang.org/x/net v0.49.0
+	golang.org/x/net v0.50.0
 	golang.org/x/sync v0.19.0
-	golang.org/x/term v0.39.0
+	golang.org/x/term v0.40.0
-	golang.org/x/text v0.33.0
+	golang.org/x/text v0.34.0
 )
 
 require (
@@ -57,7 +57,7 @@ require (
 	github.com/dsnet/compress v0.0.2-0.20230904184137-39efe44ab707 // indirect
 	github.com/ebitengine/purego v0.9.1 // indirect
 	github.com/felixge/httpsnoop v1.0.4 // indirect
-	github.com/go-json-experiment/json v0.0.0-20251027170946-4849db3c2f7e // indirect
+	github.com/go-json-experiment/json v0.0.0-20260214004413-d219187c3433 // indirect
 	github.com/go-logr/logr v1.4.3 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-ole/go-ole v1.3.0 // indirect
@@ -71,9 +71,9 @@ require (
 	github.com/hashicorp/go-memdb v1.3.5 // indirect
 	github.com/hashicorp/golang-lru v1.0.2 // indirect
 	github.com/hashicorp/golang-lru/v2 v2.0.7 // indirect
-	github.com/klauspost/compress v1.18.3 // indirect
+	github.com/klauspost/compress v1.18.4 // indirect
 	github.com/klauspost/pgzip v1.2.6 // indirect
-	github.com/lufia/plan9stats v0.0.0-20251013123823-9fd1530e3ec3 // indirect
+	github.com/lufia/plan9stats v0.0.0-20260216142805-b3301c5f2a88 // indirect
 	github.com/magiconair/properties v1.8.10 // indirect
 	github.com/mattn/go-colorable v0.1.14 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
@@ -109,16 +109,16 @@ require (
 	github.com/valyala/fasttemplate v1.2.2 // indirect
 	github.com/yusufpapurcu/wmi v1.2.4 // indirect
 	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
-	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.64.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.65.0 // indirect
-	go.opentelemetry.io/otel v1.39.0 // indirect
+	go.opentelemetry.io/otel v1.40.0 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.37.0 // indirect
-	go.opentelemetry.io/otel/metric v1.39.0 // indirect
+	go.opentelemetry.io/otel/metric v1.40.0 // indirect
-	go.opentelemetry.io/otel/trace v1.39.0 // indirect
+	go.opentelemetry.io/otel/trace v1.40.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.7.1 // indirect
 	go.yaml.in/yaml/v2 v2.4.3 // indirect
 	go4.org v0.0.0-20260112195520-a5071408f32f // indirect
-	golang.org/x/crypto v0.47.0 // indirect
+	golang.org/x/crypto v0.48.0 // indirect
-	golang.org/x/sys v0.40.0 // indirect
+	golang.org/x/sys v0.41.0 // indirect
 	golang.org/x/time v0.14.0 // indirect
 	google.golang.org/protobuf v1.36.11 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

go.sum

@@ -76,8 +76,8 @@ github.com/fatih/color v1.16.0 h1:zmkK9Ngbjj+K0yRhTVONQh1p/HknKYSlNT+vZCzyokM=
 github.com/fatih/color v1.16.0/go.mod h1:fL2Sau1YI5c0pdGEVCbKQbLXB6edEj1ZgiY4NijnWvE=
 github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
 github.com/felixge/httpsnoop v1.0.4/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
-github.com/go-json-experiment/json v0.0.0-20251027170946-4849db3c2f7e h1:Lf/gRkoycfOBPa42vU2bbgPurFong6zXeFtPoxholzU=
+github.com/go-json-experiment/json v0.0.0-20260214004413-d219187c3433 h1:vymEbVwYFP/L05h5TKQxvkXoKxNvTpjxYKdF1Nlwuao=
-github.com/go-json-experiment/json v0.0.0-20251027170946-4849db3c2f7e/go.mod h1:uNVvRXArCGbZ508SxYYTC5v1JWoz2voff5pm25jU1Ok=
+github.com/go-json-experiment/json v0.0.0-20260214004413-d219187c3433/go.mod h1:tphK2c80bpPhMOI4v6bIc2xWywPfbqi1Z06+RcrMkDg=
 github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
 github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
 github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
@@ -96,8 +96,8 @@ github.com/gofrs/uuid v4.2.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRx
 github.com/gofrs/uuid v4.3.1+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRxnplIgP/c0N/04lM=
 github.com/gofrs/uuid v4.4.0+incompatible h1:3qXRTX8/NbyulANqlc0lchS1gqAVxRgsuW1YrTJupqA=
 github.com/gofrs/uuid v4.4.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRxnplIgP/c0N/04lM=
-github.com/gomarkdown/markdown v0.0.0-20250810172220-2e2c11897d1a h1:l7A0loSszR5zHd/qK53ZIHMO8b3bBSmENnQ6eKnUT0A=
+github.com/gomarkdown/markdown v0.0.0-20260217112301-37c66b85d6ab h1:VYNivV7P8IRHUam2swVUNkhIdp0LRRFKe4hXNnoZKTc=
-github.com/gomarkdown/markdown v0.0.0-20250810172220-2e2c11897d1a/go.mod h1:JDGcbDT52eL4fju3sZ4TeHGsQwhG9nbDV21aMyhwPoA=
+github.com/gomarkdown/markdown v0.0.0-20260217112301-37c66b85d6ab/go.mod h1:JDGcbDT52eL4fju3sZ4TeHGsQwhG9nbDV21aMyhwPoA=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
@@ -130,8 +130,8 @@ github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs
 github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/klauspost/compress v1.4.1/go.mod h1:RyIbtBH6LamlWaDj8nUwkbUhJ87Yi3uG0guNDohfE1A=
-github.com/klauspost/compress v1.18.3 h1:9PJRvfbmTabkOX8moIpXPbMMbYN60bWImDDU7L+/6zw=
+github.com/klauspost/compress v1.18.4 h1:RPhnKRAQ4Fh8zU2FY/6ZFDwTVTxgJ/EMydqSTzE9a2c=
-github.com/klauspost/compress v1.18.3/go.mod h1:R0h/fSBs8DE4ENlcrlib3PsXS61voFxhIs2DeRhCvJ4=
+github.com/klauspost/compress v1.18.4/go.mod h1:R0h/fSBs8DE4ENlcrlib3PsXS61voFxhIs2DeRhCvJ4=
 github.com/klauspost/cpuid v1.2.0/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgoMS4s3ek=
 github.com/klauspost/pgzip v1.2.6 h1:8RXeL5crjEUFnR2/Sn6GJNWtSQ3Dk8pq4CL3jvdDyjU=
 github.com/klauspost/pgzip v1.2.6/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQKQE9RUs=
@@ -150,8 +150,8 @@ github.com/labstack/gommon v0.4.2 h1:F8qTUNXgG1+6WQmqoUWnz8WiEU60mXVVw0P4ht1WRA0
 github.com/labstack/gommon v0.4.2/go.mod h1:QlUFxVM+SNXhDL/Z7YhocGIBYOiwB0mXm1+1bAPHPyU=
 github.com/ledongthuc/pdf v0.0.0-20220302134840-0c2507a12d80 h1:6Yzfa6GP0rIo/kULo2bwGEkFvCePZ3qHDDTC3/J9Swo=
 github.com/ledongthuc/pdf v0.0.0-20220302134840-0c2507a12d80/go.mod h1:imJHygn/1yfhB7XSJJKlFZKl/J+dCPAknuiaGOshXAs=
-github.com/lufia/plan9stats v0.0.0-20251013123823-9fd1530e3ec3 h1:PwQumkgq4/acIiZhtifTV5OUqqiP82UAl0h87xj/l9k=
+github.com/lufia/plan9stats v0.0.0-20260216142805-b3301c5f2a88 h1:PTw+yKnXcOFCR6+8hHTyWBeQ/P4Nb7dd4/0ohEcWQuM=
-github.com/lufia/plan9stats v0.0.0-20251013123823-9fd1530e3ec3/go.mod h1:autxFIvghDt3jPTLoqZ9OZ7s9qTGNAWmYCjVFWPX/zg=
+github.com/lufia/plan9stats v0.0.0-20260216142805-b3301c5f2a88/go.mod h1:autxFIvghDt3jPTLoqZ9OZ7s9qTGNAWmYCjVFWPX/zg=
 github.com/magiconair/properties v1.8.10 h1:s31yESBquKXCV9a/ScB3ESkOjUYYv+X0rg8SYxI99mE=
 github.com/magiconair/properties v1.8.10/go.mod h1:Dhd985XPs7jluiymwWYZ0G4Z61jb3vdS329zhj2hYo0=
 github.com/mattn/go-colorable v0.1.14 h1:9A9LHSqF/7dyVVX6g0U9cwm9pG3kP9gSzcuIPHPsaIE=
@@ -213,8 +213,8 @@ github.com/prometheus/procfs v0.19.2/go.mod h1:M0aotyiemPhBCM0z5w87kL22CxfcH05Zp
 github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
 github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
-github.com/shirou/gopsutil/v4 v4.25.12 h1:e7PvW/0RmJ8p8vPGJH4jvNkOyLmbkXgXW4m6ZPic6CY=
+github.com/shirou/gopsutil/v4 v4.26.1 h1:TOkEyriIXk2HX9d4isZJtbjXbEjf5qyKPAzbzY0JWSo=
-github.com/shirou/gopsutil/v4 v4.25.12/go.mod h1:EivAfP5x2EhLp2ovdpKSozecVXn1TmuG7SMzs/Wh4PU=
+github.com/shirou/gopsutil/v4 v4.26.1/go.mod h1:medLI9/UNAb0dOI9Q3/7yWSqKkj00u+1tgY8nvv41pc=
 github.com/sirupsen/logrus v1.9.4 h1:TsZE7l11zFCLZnZ+teH4Umoq5BhEIfIzfRDZ1Uzql2w=
 github.com/sirupsen/logrus v1.9.4/go.mod h1:ftWc9WdOfJ0a92nsE2jF5u5ZwH8Bv2zdeOC42RjbV2g=
 github.com/sorairolake/lzip-go v0.3.8 h1:j5Q2313INdTA80ureWYRhX+1K78mUXfMoPZCw/ivWik=
@@ -257,22 +257,22 @@ github.com/yusufpapurcu/wmi v1.2.4 h1:zFUKzehAFReQwLys1b/iSMl+JQGSCSjtVqQn9bBrPo
 github.com/yusufpapurcu/wmi v1.2.4/go.mod h1:SBZ9tNy3G9/m5Oi98Zks0QjeHVDvuK0qfxQmPyzfmi0=
 go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
 go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
-go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.64.0 h1:ssfIgGNANqpVFCndZvcuyKbl0g+UAVcbBcqGkG28H0Y=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.65.0 h1:7iP2uCb7sGddAr30RRS6xjKy7AZ2JtTOPA3oolgVSw8=
-go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.64.0/go.mod h1:GQ/474YrbE4Jx8gZ4q5I4hrhUzM6UPzyrqJYV2AqPoQ=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.65.0/go.mod h1:c7hN3ddxs/z6q9xwvfLPk+UHlWRQyaeR1LdgfL/66l0=
-go.opentelemetry.io/otel v1.39.0 h1:8yPrr/S0ND9QEfTfdP9V+SiwT4E0G7Y5MO7p85nis48=
+go.opentelemetry.io/otel v1.40.0 h1:oA5YeOcpRTXq6NN7frwmwFR0Cn3RhTVZvXsP4duvCms=
-go.opentelemetry.io/otel v1.39.0/go.mod h1:kLlFTywNWrFyEdH0oj2xK0bFYZtHRYUdv1NklR/tgc8=
+go.opentelemetry.io/otel v1.40.0/go.mod h1:IMb+uXZUKkMXdPddhwAHm6UfOwJyh4ct1ybIlV14J0g=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.37.0 h1:Ahq7pZmv87yiyn3jeFz/LekZmPLLdKejuO3NcK9MssM=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.37.0/go.mod h1:MJTqhM0im3mRLw1i8uGHnCvUEeS7VwRyxlLC78PA18M=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.19.0 h1:IeMeyr1aBvBiPVYihXIaeIZba6b8E1bYp7lbdxK8CQg=
 go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.19.0/go.mod h1:oVdCUtjq9MK9BlS7TtucsQwUcXcymNiEDjgDD2jMtZU=
-go.opentelemetry.io/otel/metric v1.39.0 h1:d1UzonvEZriVfpNKEVmHXbdf909uGTOQjA0HF0Ls5Q0=
+go.opentelemetry.io/otel/metric v1.40.0 h1:rcZe317KPftE2rstWIBitCdVp89A2HqjkxR3c11+p9g=
-go.opentelemetry.io/otel/metric v1.39.0/go.mod h1:jrZSWL33sD7bBxg1xjrqyDjnuzTUB0x1nBERXd7Ftcs=
+go.opentelemetry.io/otel/metric v1.40.0/go.mod h1:ib/crwQH7N3r5kfiBZQbwrTge743UDc7DTFVZrrXnqc=
-go.opentelemetry.io/otel/sdk v1.39.0 h1:nMLYcjVsvdui1B/4FRkwjzoRVsMK8uL/cj0OyhKzt18=
+go.opentelemetry.io/otel/sdk v1.40.0 h1:KHW/jUzgo6wsPh9At46+h4upjtccTmuZCFAc9OJ71f8=
-go.opentelemetry.io/otel/sdk v1.39.0/go.mod h1:vDojkC4/jsTJsE+kh+LXYQlbL8CgrEcwmt1ENZszdJE=
+go.opentelemetry.io/otel/sdk v1.40.0/go.mod h1:Ph7EFdYvxq72Y8Li9q8KebuYUr2KoeyHx0DRMKrYBUE=
-go.opentelemetry.io/otel/sdk/metric v1.39.0 h1:cXMVVFVgsIf2YL6QkRF4Urbr/aMInf+2WKg+sEJTtB8=
+go.opentelemetry.io/otel/sdk/metric v1.40.0 h1:mtmdVqgQkeRxHgRv4qhyJduP3fYJRMX4AtAlbuWdCYw=
-go.opentelemetry.io/otel/sdk/metric v1.39.0/go.mod h1:xq9HEVH7qeX69/JnwEfp6fVq5wosJsY1mt4lLfYdVew=
+go.opentelemetry.io/otel/sdk/metric v1.40.0/go.mod h1:4Z2bGMf0KSK3uRjlczMOeMhKU2rhUqdWNoKcYrtcBPg=
-go.opentelemetry.io/otel/trace v1.39.0 h1:2d2vfpEDmCJ5zVYz7ijaJdOF59xLomrvj7bjt6/qCJI=
+go.opentelemetry.io/otel/trace v1.40.0 h1:WA4etStDttCSYuhwvEa8OP8I5EWu24lkOzp+ZYblVjw=
-go.opentelemetry.io/otel/trace v1.39.0/go.mod h1:88w4/PnZSazkGzz/w84VHpQafiU4EtqqlVdxWy+rNOA=
+go.opentelemetry.io/otel/trace v1.40.0/go.mod h1:zeAhriXecNGP/s2SEG3+Y8X9ujcJOTqQ5RgdEJcawiA=
 go.opentelemetry.io/proto/otlp v1.7.1 h1:gTOMpGDb0WTBOP8JaO72iL3auEZhVmAQg4ipjOVAtj4=
 go.opentelemetry.io/proto/otlp v1.7.1/go.mod h1:b2rVh6rfI/s2pHWNlB7ILJcRALpcNDzKhACevjI+ZnE=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
@@ -285,10 +285,10 @@ go.yaml.in/yaml/v2 v2.4.3 h1:6gvOSjQoTB3vt1l+CU+tSyi/HOjfOjRLJ4YwYZGwRO0=
 go.yaml.in/yaml/v2 v2.4.3/go.mod h1:zSxWcmIDjOzPXpjlTTbAsKokqkDNAVtZO0WOMiT90s8=
 go4.org v0.0.0-20260112195520-a5071408f32f h1:ziUVAjmTPwQMBmYR1tbdRFJPtTcQUI12fH9QQjfb0Sw=
 go4.org v0.0.0-20260112195520-a5071408f32f/go.mod h1:ZRJnO5ZI4zAwMFp+dS1+V6J6MSyAowhRqAE+DPa1Xp0=
-golang.org/x/crypto v0.47.0 h1:V6e3FRj+n4dbpw86FJ8Fv7XVOql7TEwpHapKoMJ/GO8=
+golang.org/x/crypto v0.48.0 h1:/VRzVqiRSggnhY7gNRxPauEQ5Drw9haKdM0jqfcCFts=
-golang.org/x/crypto v0.47.0/go.mod h1:ff3Y9VzzKbwSSEzWqJsJVBnWmRwRSHt/6Op5n9bQc4A=
+golang.org/x/crypto v0.48.0/go.mod h1:r0kV5h3qnFPlQnBSrULhlsRfryS2pmewsg+XfMgkVos=
-golang.org/x/net v0.49.0 h1:eeHFmOGUTtaaPSGNmjBKpbng9MulQsJURQUAfUwY++o=
+golang.org/x/net v0.50.0 h1:ucWh9eiCGyDR3vtzso0WMQinm2Dnt8cFMuQa9K33J60=
-golang.org/x/net v0.49.0/go.mod h1:/ysNB2EvaqvesRkuLAyjI1ycPZlQHM3q01F02UY/MV8=
+golang.org/x/net v0.50.0/go.mod h1:UgoSli3F/pBgdJBHCTc+tp3gmrU4XswgGRgtnwWTfyM=
 golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
 golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/sys v0.0.0-20190916202348-b4ddaad3f8a3/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -296,12 +296,12 @@ golang.org/x/sys v0.0.0-20201204225414-ed752295db88/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210616094352-59db8d763f22/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.40.0 h1:DBZZqJ2Rkml6QMQsZywtnjnnGvHza6BTfYFWY9kjEWQ=
+golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
-golang.org/x/sys v0.40.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
-golang.org/x/term v0.39.0 h1:RclSuaJf32jOqZz74CkPA9qFuVTX7vhLlpfj/IGWlqY=
+golang.org/x/term v0.40.0 h1:36e4zGLqU4yhjlmxEaagx2KuYbJq3EwY8K943ZsHcvg=
-golang.org/x/term v0.39.0/go.mod h1:yxzUCTP/U+FzoxfdKmLaA0RV1WgE0VY7hXBwKtY/4ww=
+golang.org/x/term v0.40.0/go.mod h1:w2P8uVp06p2iyKKuvXIm7N/y0UCRt3UfJTfZ7oOpglM=
-golang.org/x/text v0.33.0 h1:B3njUFyqtHDUI5jMn1YIr5B0IE2U0qck04r6d4KPAxE=
+golang.org/x/text v0.34.0 h1:oL/Qq0Kdaqxa1KbNeMKwQq0reLCCaFtqu2eNuSeNHbk=
-golang.org/x/text v0.33.0/go.mod h1:LuMebE6+rBincTi9+xWTY8TztLzKHc/9C1uBCG27+q8=
+golang.org/x/text v0.34.0/go.mod h1:homfLqTYRFyVYemLBFl5GgL/DWEiH5wcsQ5gSh1yziA=
 golang.org/x/time v0.14.0 h1:MRx4UaLrDotUKUdCIqzPC48t1Y9hANFKIRpNx+Te8PI=
 golang.org/x/time v0.14.0/go.mod h1:eL/Oa2bBBK0TkX57Fyni+NgnyQQN4LitPmob2Hjnqw4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

pkg/gotenberg/context.go

@@ -10,7 +10,7 @@ import (
 type Context struct {
 	flags           ParsedFlags
 	descriptors     []ModuleDescriptor
-	moduleInstances map[string]interface{}
+	moduleInstances map[string]any
 }
 
 // NewContext creates a [Context].
@@ -22,7 +22,7 @@ func NewContext(
 	return &Context{
 		flags:           flags,
 		descriptors:     descriptors,
-		moduleInstances: make(map[string]interface{}),
+		moduleInstances: make(map[string]any),
 	}
 }
 
@@ -45,7 +45,7 @@ func (ctx *Context) ParsedFlags() ParsedFlags {
 //
 // If the module has not yet been initialized, this method
 // initializes it. Otherwise, returns the already initialized instance.
-func (ctx *Context) Module(kind interface{}) (interface{}, error) {
+func (ctx *Context) Module(kind any) (any, error) {
 	mods, err := ctx.Modules(kind)
 	if err != nil {
 		return nil, fmt.Errorf("get module: %w", err)
@@ -70,10 +70,10 @@ func (ctx *Context) Module(kind interface{}) (interface{}, error) {
 //
 // If one or more modules have not yet been initialized, this method
 // initializes them. Otherwise, returns the already initialized instances.
-func (ctx *Context) Modules(kind interface{}) ([]interface{}, error) {
+func (ctx *Context) Modules(kind any) ([]any, error) {
 	realKind := reflect.TypeOf(kind).Elem()
 
-	var mods []interface{}
+	var mods []any
 
 	for _, desc := range ctx.descriptors {
 		newInstance := desc.New()
@@ -101,7 +101,7 @@ func (ctx *Context) Modules(kind interface{}) ([]interface{}, error) {
 
 // loadModule calls the Provision and/or Validate methods of the requested
 // module if it satisfies the [Provisioner] and/or [Validator] interfaces.
-func (ctx *Context) loadModule(id string, instance interface{}) error {
+func (ctx *Context) loadModule(id string, instance any) error {
 	if prov, ok := instance.(Provisioner); ok {
 		// The instance can be provisioned.
 		err := prov.Provision(ctx)

pkg/gotenberg/context_test.go

@@ -9,7 +9,7 @@ func TestContext_Module(t *testing.T) {
 	for _, tc := range []struct {
 		scenario    string
 		mods        []ModuleDescriptor
-		kind        interface{}
+		kind        any
 		expectError bool
 	}{
 		{
@@ -80,7 +80,7 @@ func TestContext_Modules(t *testing.T) {
 	for _, tc := range []struct {
 		scenario    string
 		mods        []ModuleDescriptor
-		kind        interface{}
+		kind        any
 		expectError bool
 	}{
 		{
@@ -151,12 +151,12 @@ func TestContext_Modules(t *testing.T) {
 func TestContext_loadModule(t *testing.T) {
 	for _, tc := range []struct {
 		scenario    string
-		instance    interface{}
+		instance    any
 		expectError bool
 	}{
 		{
 			scenario: "module with error on provision",
-			instance: func() interface{} {
+			instance: func() any {
 				mod := &struct {
 					ModuleMock
 					ProvisionerMock
@@ -171,7 +171,7 @@ func TestContext_loadModule(t *testing.T) {
 		},
 		{
 			scenario: "module with error on validation",
-			instance: func() interface{} {
+			instance: func() any {
 				mod := &struct {
 					ModuleMock
 					ValidatorMock
@@ -186,7 +186,7 @@ func TestContext_loadModule(t *testing.T) {
 		},
 		{
 			scenario: "success",
-			instance: func() interface{} {
+			instance: func() any {
 				mod := &struct {
 					ModuleMock
 					ValidatorMock

pkg/gotenberg/debug.go

@@ -4,17 +4,19 @@ import (
 	"runtime"
 	"sort"
 	"sync"
+	"time"
 
 	flag "github.com/spf13/pflag"
 )
 
 // DebugInfo gathers data for debugging.
 type DebugInfo struct {
-	Version               string                            `json:"version"`
+	Version               string                    `json:"version"`
-	Architecture          string                            `json:"architecture"`
+	Timezone              string                    `json:"timezone"`
-	Modules               []string                          `json:"modules"`
+	Architecture          string                    `json:"architecture"`
-	ModulesAdditionalData map[string]map[string]interface{} `json:"modules_additional_data"`
+	Modules               []string                  `json:"modules"`
-	Flags                 map[string]interface{}            `json:"flags"`
+	ModulesAdditionalData map[string]map[string]any `json:"modules_additional_data"`
+	Flags                 map[string]any            `json:"flags"`
 }
 
 // BuildDebug builds the debug data from modules.
@@ -24,10 +26,11 @@ func BuildDebug(ctx *Context) {
 
 	debug = &DebugInfo{
 		Version:               Version,
+		Timezone:              time.Now().Location().String(),
 		Architecture:          runtime.GOARCH,
 		Modules:               make([]string, len(ctx.moduleInstances)),
-		ModulesAdditionalData: make(map[string]map[string]interface{}),
+		ModulesAdditionalData: make(map[string]map[string]any),
-		Flags:                 make(map[string]interface{}),
+		Flags:                 make(map[string]any),
 	}
 
 	i := 0

pkg/gotenberg/debug_test.go

@@ -13,6 +13,8 @@ func TestBuildDebug(t *testing.T) {
 		t.Errorf("Debug() should return empty debug data")
 	}
 
+	t.Setenv("TZ", "UTC")
+
 	fs := flag.NewFlagSet("gotenberg", flag.ExitOnError)
 	fs.String("foo", "bar", "Set foo")
 	ctx := NewContext(ParsedFlags{
@@ -31,8 +33,8 @@ func TestBuildDebug(t *testing.T) {
 		mod2.DescriptorMock = func() ModuleDescriptor {
 			return ModuleDescriptor{ID: "bar", New: func() Module { return mod2 }}
 		}
-		mod2.DebugMock = func() map[string]interface{} {
+		mod2.DebugMock = func() map[string]any {
-			return map[string]interface{}{
+			return map[string]any{
 				"foo": "bar",
 			}
 		}
@@ -51,17 +53,18 @@ func TestBuildDebug(t *testing.T) {
 
 	expect := DebugInfo{
 		Version:      Version,
+		Timezone:     "UTC",
 		Architecture: runtime.GOARCH,
 		Modules: []string{
 			"bar",
 			"foo",
 		},
-		ModulesAdditionalData: map[string]map[string]interface{}{
+		ModulesAdditionalData: map[string]map[string]any{
 			"bar": {
 				"foo": "bar",
 			},
 		},
-		Flags: map[string]interface{}{
+		Flags: map[string]any{
 			"foo": "bar",
 		},
 	}

pkg/gotenberg/logging.go

@@ -32,22 +32,22 @@ func NewLeveledLogger(logger *zap.Logger) *LeveledLogger {
 }
 
 // Error logs a message at the error level using the wrapped zap.Logger.
-func (leveled LeveledLogger) Error(msg string, keysAndValues ...interface{}) {
+func (leveled LeveledLogger) Error(msg string, keysAndValues ...any) {
 	leveled.logger.Error(fmt.Sprintf("%s: %+v", msg, keysAndValues))
 }
 
 // Warn logs a message at the warning level using the wrapped zap.Logger.
-func (leveled LeveledLogger) Warn(msg string, keysAndValues ...interface{}) {
+func (leveled LeveledLogger) Warn(msg string, keysAndValues ...any) {
 	leveled.logger.Warn(fmt.Sprintf("%s: %+v", msg, keysAndValues))
 }
 
 // Info logs a message at the info level using the wrapped zap.Logger.
-func (leveled LeveledLogger) Info(msg string, keysAndValues ...interface{}) {
+func (leveled LeveledLogger) Info(msg string, keysAndValues ...any) {
 	leveled.logger.Info(fmt.Sprintf("%s: %+v", msg, keysAndValues))
 }
 
 // Debug logs a message at the debug level using the wrapped zap.Logger.
-func (leveled LeveledLogger) Debug(msg string, keysAndValues ...interface{}) {
+func (leveled LeveledLogger) Debug(msg string, keysAndValues ...any) {
 	leveled.logger.Debug(fmt.Sprintf("%s: %+v", msg, keysAndValues))
 }
 

pkg/gotenberg/mocks.go

@@ -35,10 +35,10 @@ func (mod *ValidatorMock) Validate() error {
 }
 
 type DebuggableMock struct {
-	DebugMock func() map[string]interface{}
+	DebugMock func() map[string]any
 }
 
-func (mod *DebuggableMock) Debug() map[string]interface{} {
+func (mod *DebuggableMock) Debug() map[string]any {
 	return mod.DebugMock()
 }
 
@@ -50,8 +50,8 @@ type PdfEngineMock struct {
 	SplitMock         func(ctx context.Context, logger *zap.Logger, mode SplitMode, inputPath, outputDirPath string) ([]string, error)
 	FlattenMock       func(ctx context.Context, logger *zap.Logger, inputPath string) error
 	ConvertMock       func(ctx context.Context, logger *zap.Logger, formats PdfFormats, inputPath, outputPath string) error
-	ReadMetadataMock  func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error)
+	ReadMetadataMock  func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error)
-	WriteMetadataMock func(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error
+	WriteMetadataMock func(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error
 	EncryptMock       func(ctx context.Context, logger *zap.Logger, inputPath, userPassword, ownerPassword string) error
 	EmbedFilesMock    func(ctx context.Context, logger *zap.Logger, filePaths []string, inputPath string) error
 }
@@ -72,11 +72,11 @@ func (engine *PdfEngineMock) Convert(ctx context.Context, logger *zap.Logger, fo
 	return engine.ConvertMock(ctx, logger, formats, inputPath, outputPath)
 }
 
-func (engine *PdfEngineMock) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+func (engine *PdfEngineMock) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
 	return engine.ReadMetadataMock(ctx, logger, inputPath)
 }
 
-func (engine *PdfEngineMock) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+func (engine *PdfEngineMock) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 	return engine.WriteMetadataMock(ctx, logger, metadata, inputPath)
 }
 

pkg/gotenberg/modules.go

@@ -78,7 +78,7 @@ type SystemLogger interface {
 // Debuggable is a module interface for modules which want to provide
 // additional debug data.
 type Debuggable interface {
-	Debug() map[string]interface{}
+	Debug() map[string]any
 }
 
 // MustRegisterModule registers a module.

pkg/gotenberg/pdfengine.go

@@ -133,10 +133,10 @@ type PdfEngine interface {
 	Convert(ctx context.Context, logger *zap.Logger, formats PdfFormats, inputPath, outputPath string) error
 
 	// ReadMetadata extracts the metadata of a given PDF file.
-	ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error)
+	ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error)
 
 	// WriteMetadata writes the metadata into a given PDF file.
-	WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error
+	WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error
 
 	// Encrypt adds password protection to a PDF file.
 	// The userPassword is required to open the document.

pkg/gotenberg/supervisor.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"sync"
 	"sync/atomic"
 
 	"go.uber.org/zap"
@@ -79,27 +80,38 @@ type processSupervisor struct {
 	process         Process
 	maxReqLimit     int64
 	maxQueueSize    int64
-	mutexChan       chan struct{}
+	maxConcurrency  int64
+	semaphore       chan struct{}
 	firstStart      atomic.Bool
+	firstStartOnce  sync.Once
+	firstStartErr   error
 	reqCounter      atomic.Int64
 	reqQueueSize    atomic.Int64
 	restartsCounter atomic.Int64
 	isRestarting    atomic.Bool
+	activeTasks     atomic.Int64
+	restartMutex    sync.Mutex
 }
 
 // NewProcessSupervisor initializes a new [ProcessSupervisor].
-func NewProcessSupervisor(logger *zap.Logger, process Process, maxReqLimit, maxQueueSize int64) ProcessSupervisor {
+func NewProcessSupervisor(logger *zap.Logger, process Process, maxReqLimit, maxQueueSize, maxConcurrency int64) ProcessSupervisor {
+	if maxConcurrency < 1 {
+		maxConcurrency = 1
+	}
+
 	b := &processSupervisor{
-		logger:       logger,
+		logger:         logger,
-		process:      process,
+		process:        process,
-		mutexChan:    make(chan struct{}, 1),
+		semaphore:      make(chan struct{}, maxConcurrency),
-		maxReqLimit:  maxReqLimit,
+		maxReqLimit:    maxReqLimit,
-		maxQueueSize: maxQueueSize,
+		maxQueueSize:   maxQueueSize,
+		maxConcurrency: maxConcurrency,
 	}
 	b.reqCounter.Store(0)
 	b.reqQueueSize.Store(0)
 	b.restartsCounter.Store(0)
 	b.isRestarting.Store(false)
+	b.activeTasks.Store(0)
 
 	return b
 }
@@ -130,15 +142,7 @@ func (s *processSupervisor) Shutdown() error {
 }
 
 func (s *processSupervisor) restart() error {
-	if s.isRestarting.Load() {
-		s.logger.Debug("process already restarting, skip restart")
-
-		return ErrProcessAlreadyRestarting
-	}
-
 	s.logger.Debug("restart process")
-	s.isRestarting.Store(true)
-	defer s.isRestarting.Store(false)
 
 	err := s.Shutdown()
 	if err != nil {
@@ -197,33 +201,43 @@ func (s *processSupervisor) Run(ctx context.Context, logger *zap.Logger, task fu
 	for {
 		err := func() error {
 			select {
-			case s.mutexChan <- struct{}{}:
+			case s.semaphore <- struct{}{}:
 				logger.Debug("process lock acquired")
+
+				// If a restart drain is in progress, release the slot
+				// immediately so the drain can acquire it instead.
+				if s.isRestarting.Load() {
+					<-s.semaphore
+					return ErrProcessAlreadyRestarting
+				}
+
 				s.reqQueueSize.Add(-1)
 				s.reqCounter.Add(1)
-				releaseMutexChan := true
+				s.activeTasks.Add(1)
+				releaseSemaphore := true
 
 				defer func() {
-					if releaseMutexChan {
+					s.activeTasks.Add(-1)
+					if releaseSemaphore {
 						logger.Debug("process lock released")
-						<-s.mutexChan
+						<-s.semaphore
 					}
 				}()
 
 				if !s.firstStart.Load() {
-					err := s.runWithDeadline(ctx, func() error {
+					s.firstStartOnce.Do(func() {
-						return s.Launch()
+						s.firstStartErr = s.runWithDeadline(ctx, func() error {
+							return s.Launch()
+						})
 					})
-					if err != nil {
+					if s.firstStartErr != nil {
-						return fmt.Errorf("process first start: %w", err)
+						return fmt.Errorf("process first start: %w", s.firstStartErr)
 					}
 				}
 
 				if !s.Healthy() {
 					s.logger.Debug("process is unhealthy, cannot handle task, restarting...")
-					err := s.runWithDeadline(ctx, func() error {
+					err := s.doRestart(ctx)
-						return s.restart()
-					})
 					if err != nil {
 						return fmt.Errorf("process restart before task: %w", err)
 					}
@@ -232,19 +246,21 @@ func (s *processSupervisor) Run(ctx context.Context, logger *zap.Logger, task fu
 				err := s.runWithDeadline(ctx, task)
 
 				if s.maxReqLimit > 0 && s.reqCounter.Load() >= s.maxReqLimit {
-					s.logger.Debug("max request limit reached, restarting eagerly...")
+					// Only one goroutine should trigger the restart.
-					releaseMutexChan = false
+					if s.restartMutex.TryLock() {
+						s.logger.Debug("max request limit reached, restarting eagerly...")
+						releaseSemaphore = false
 
-					go func() {
+						go func() {
-						err := s.runWithDeadline(context.Background(), func() error {
+							restartErr := s.doRestartLocked(context.Background())
-							return s.restart()
+							s.restartMutex.Unlock()
-						})
+							if restartErr != nil {
-						if err != nil {
+								s.logger.Error(fmt.Sprintf("process restart after task: %v", restartErr))
-							s.logger.Error(fmt.Sprintf("process restart after task: %v", err))
+							}
-						}
+							logger.Debug("process lock released")
-						logger.Debug("process lock released")
+							<-s.semaphore
-						<-s.mutexChan
+						}()
-					}()
+					}
 				}
 
 				// Note: no error wrapping because it leaks on Chromium console exceptions output.
@@ -259,7 +275,6 @@ func (s *processSupervisor) Run(ctx context.Context, logger *zap.Logger, task fu
 
 		if errors.Is(err, ErrProcessAlreadyRestarting) {
 			logger.Debug("process is already restarting, trying to acquire process lock again...")
-			s.reqQueueSize.Add(1)
 			continue
 		}
 
@@ -268,6 +283,47 @@ func (s *processSupervisor) Run(ctx context.Context, logger *zap.Logger, task fu
 	}
 }
 
+// doRestart coordinates a process restart, draining all active concurrent
+// tasks before stopping and restarting the process.
+func (s *processSupervisor) doRestart(ctx context.Context) error {
+	s.restartMutex.Lock()
+	defer s.restartMutex.Unlock()
+
+	return s.doRestartLocked(ctx)
+}
+
+// doRestartLocked performs the restart drain logic. The caller must hold restartMutex.
+func (s *processSupervisor) doRestartLocked(ctx context.Context) error {
+	s.isRestarting.Store(true)
+	defer s.isRestarting.Store(false)
+
+	// Drain all other active semaphore slots so no other tasks are running during the restart.
+	slotsToAcquire := s.maxConcurrency - 1
+	acquired := make([]struct{}, 0, slotsToAcquire)
+
+	for range slotsToAcquire {
+		select {
+		case s.semaphore <- struct{}{}:
+			acquired = append(acquired, struct{}{})
+		case <-ctx.Done():
+			for range acquired {
+				<-s.semaphore
+			}
+			return fmt.Errorf("drain active tasks before restart: %w", ctx.Err())
+		}
+	}
+
+	err := s.runWithDeadline(ctx, func() error {
+		return s.restart()
+	})
+
+	for range acquired {
+		<-s.semaphore
+	}
+
+	return err
+}
+
 func (s *processSupervisor) runWithDeadline(ctx context.Context, task func() error) error {
 	runChan := make(chan error, 1)
 	go func() {

pkg/gotenberg/supervisor_test.go

@@ -46,7 +46,7 @@ func TestProcessSupervisor_Launch(t *testing.T) {
 				},
 			}
 
-			ps := NewProcessSupervisor(logger, process, 5, 0).(*processSupervisor)
+			ps := NewProcessSupervisor(logger, process, 5, 0, 1).(*processSupervisor)
 			if tc.firstStartSet {
 				ps.firstStart.Store(true)
 			}
@@ -94,7 +94,7 @@ func TestProcessSupervisor_Shutdown(t *testing.T) {
 				},
 			}
 
-			ps := NewProcessSupervisor(logger, process, 5, 0)
+			ps := NewProcessSupervisor(logger, process, 5, 0, 1)
 			err := ps.Shutdown()
 
 			if !tc.expectError && err != nil {
@@ -110,19 +110,11 @@ func TestProcessSupervisor_Shutdown(t *testing.T) {
 
 func TestProcessSupervisor_restart(t *testing.T) {
 	for _, tc := range []struct {
-		scenario            string
+		scenario    string
-		initiallyRestarting bool
+		startError  error
-		startError          error
+		stopError   error
-		stopError           error
+		expectError bool
-		expectError         bool
-		expectedError       error
 	}{
-		{
-			scenario:            "already restarting",
-			initiallyRestarting: true,
-			expectError:         true,
-			expectedError:       ErrProcessAlreadyRestarting,
-		},
 		{
 			scenario:    "successful restart",
 			startError:  nil,
@@ -154,10 +146,7 @@ func TestProcessSupervisor_restart(t *testing.T) {
 				},
 			}
 
-			ps := NewProcessSupervisor(logger, process, 5, 0).(*processSupervisor)
+			ps := NewProcessSupervisor(logger, process, 5, 0, 1).(*processSupervisor)
-			if tc.initiallyRestarting {
-				ps.isRestarting.Store(true)
-			}
 
 			err := ps.restart()
 
@@ -168,10 +157,6 @@ func TestProcessSupervisor_restart(t *testing.T) {
 			if tc.expectError && err == nil {
 				t.Fatal("expected error but got none")
 			}
-
-			if tc.expectedError != nil && !errors.Is(err, tc.expectedError) {
-				t.Fatalf("expected error %v but got: %v", tc.expectedError, err)
-			}
 		})
 	}
 }
@@ -217,7 +202,7 @@ func TestProcessSupervisor_Healthy(t *testing.T) {
 				},
 			}
 
-			ps := NewProcessSupervisor(logger, process, 5, 0).(*processSupervisor)
+			ps := NewProcessSupervisor(logger, process, 5, 0, 1).(*processSupervisor)
 			if tc.initiallyStarted {
 				ps.firstStart.Store(true)
 			}
@@ -402,7 +387,7 @@ func TestProcessSupervisor_Run(t *testing.T) {
 				},
 			}
 
-			ps := NewProcessSupervisor(logger, process, tc.maxReqLimit, tc.maxQueueSize).(*processSupervisor)
+			ps := NewProcessSupervisor(logger, process, tc.maxReqLimit, tc.maxQueueSize, 1).(*processSupervisor)
 			if tc.initiallyStarted {
 				ps.firstStart.Store(true)
 			}
@@ -424,14 +409,12 @@ func TestProcessSupervisor_Run(t *testing.T) {
 			errorChan := make(chan error, tc.tasksToRun)
 
 			for i := 0; i < tc.tasksToRun; i++ {
-				wg.Add(1)
+				wg.Go(func() {
-				go func() {
-					defer wg.Done()
 					err := ps.Run(ctx, logger, task)
 					if err != nil {
 						errorChan <- err
 					}
-				}()
+				})
 			}
 
 			wg.Wait()
@@ -452,8 +435,8 @@ func TestProcessSupervisor_Run(t *testing.T) {
 			}
 
 			// Making sure restarts are finished.
-			ps.mutexChan <- struct{}{}
+			ps.semaphore <- struct{}{}
-			<-ps.mutexChan
+			<-ps.semaphore
 
 			if startCalls.Load() != tc.expectedStartCalls {
 				t.Errorf("expected %d process.Start calls, got %d", tc.expectedStartCalls, startCalls.Load())
@@ -488,7 +471,7 @@ func TestProcessSupervisor_runWithDeadline(t *testing.T) {
 		},
 	} {
 		t.Run(tc.scenario, func(t *testing.T) {
-			ps := NewProcessSupervisor(zap.NewNop(), new(ProcessMock), 0, 0).(*processSupervisor)
+			ps := NewProcessSupervisor(zap.NewNop(), new(ProcessMock), 0, 0, 1).(*processSupervisor)
 
 			ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
 			if tc.ctxDone {
@@ -522,10 +505,10 @@ func TestProcessSupervisor_ReqQueueSize(t *testing.T) {
 			return true
 		},
 	}
-	ps := NewProcessSupervisor(logger, process, 0, 0).(*processSupervisor)
+	ps := NewProcessSupervisor(logger, process, 0, 0, 1).(*processSupervisor)
 
 	// Simulating a lock.
-	ps.mutexChan <- struct{}{}
+	ps.semaphore <- struct{}{}
 
 	if ps.ReqQueueSize() != 0 {
 		t.Fatalf("expected queue size to be 0 but got %d", ps.ReqQueueSize())
@@ -537,17 +520,15 @@ func TestProcessSupervisor_ReqQueueSize(t *testing.T) {
 	var wg sync.WaitGroup
 	errorChan := make(chan error, 10)
 
-	for i := 0; i < 10; i++ {
+	for range 10 {
-		wg.Add(1)
+		wg.Go(func() {
-		go func() {
-			defer wg.Done()
 			err := ps.Run(ctx, logger, func() error {
 				return nil
 			})
 			if err != nil {
 				errorChan <- err
 			}
-		}()
+		})
 	}
 
 	// We have to wait a little bit so that the request queue size may change.
@@ -623,7 +604,7 @@ func TestProcessSupervisor_RestartsCount(t *testing.T) {
 				},
 			}
 
-			ps := NewProcessSupervisor(logger, process, 0, 0).(*processSupervisor)
+			ps := NewProcessSupervisor(logger, process, 0, 0, 1).(*processSupervisor)
 			ps.restartsCounter.Store(tc.initialRestartsCount)
 
 			for i := 0; i < tc.restartAttempts; i++ {
@@ -637,3 +618,122 @@ func TestProcessSupervisor_RestartsCount(t *testing.T) {
 		})
 	}
 }
+
+func TestProcessSupervisor_ConcurrentRun(t *testing.T) {
+	logger := zap.NewNop()
+
+	var startCalls atomic.Int64
+	process := &ProcessMock{
+		StartMock: func(logger *zap.Logger) error {
+			startCalls.Add(1)
+			return nil
+		},
+		StopMock: func(logger *zap.Logger) error {
+			return nil
+		},
+		HealthyMock: func(logger *zap.Logger) bool {
+			return true
+		},
+	}
+
+	maxConcurrency := int64(3)
+	ps := NewProcessSupervisor(logger, process, 0, 0, maxConcurrency).(*processSupervisor)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	var running atomic.Int64
+	var maxRunning atomic.Int64
+
+	var wg sync.WaitGroup
+	tasks := 6
+
+	for range tasks {
+		wg.Go(func() {
+			err := ps.Run(ctx, logger, func() error {
+				cur := running.Add(1)
+				for {
+					old := maxRunning.Load()
+					if cur <= old || maxRunning.CompareAndSwap(old, cur) {
+						break
+					}
+				}
+				time.Sleep(50 * time.Millisecond)
+				running.Add(-1)
+				return nil
+			})
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+		})
+	}
+
+	wg.Wait()
+
+	observed := maxRunning.Load()
+	if observed > maxConcurrency {
+		t.Fatalf("expected at most %d concurrent tasks, but observed %d", maxConcurrency, observed)
+	}
+	if observed < 2 {
+		t.Fatalf("expected concurrent execution (at least 2 tasks running simultaneously), but observed max %d", observed)
+	}
+
+	if startCalls.Load() != 1 {
+		t.Errorf("expected 1 start call, got %d", startCalls.Load())
+	}
+}
+
+func TestProcessSupervisor_RestartDrainsAllSlots(t *testing.T) {
+	logger := zap.NewNop()
+
+	process := &ProcessMock{
+		StartMock: func(logger *zap.Logger) error {
+			return nil
+		},
+		StopMock: func(logger *zap.Logger) error {
+			return nil
+		},
+		HealthyMock: func(logger *zap.Logger) bool {
+			return true
+		},
+	}
+
+	maxConcurrency := int64(3)
+	ps := NewProcessSupervisor(logger, process, 3, 0, maxConcurrency).(*processSupervisor)
+	ps.firstStart.Store(true)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	var wg sync.WaitGroup
+	tasks := 3
+
+	for range tasks {
+		wg.Go(func() {
+			err := ps.Run(ctx, logger, func() error {
+				time.Sleep(50 * time.Millisecond)
+				return nil
+			})
+			if err != nil {
+				t.Errorf("unexpected error: %v", err)
+			}
+		})
+	}
+
+	wg.Wait()
+
+	// Wait for the async restart goroutine to complete.
+	deadline := time.After(5 * time.Second)
+	for ps.RestartsCount() < 1 {
+		select {
+		case <-deadline:
+			t.Fatal("timed out waiting for restart to complete")
+		default:
+			time.Sleep(10 * time.Millisecond)
+		}
+	}
+
+	if ps.RestartsCount() != 1 {
+		t.Fatalf("expected 1 restart, got %d", ps.RestartsCount())
+	}
+}

pkg/modules/api/formdata.go

@@ -439,7 +439,7 @@ func (form *FormData) append(err error) {
 // mustValue binds the target interface with a form field. If the value is
 // empty or the "key" does not exist, it binds the default value. Currently,
 // only the string, bool, int, float64 and time.Duration types are bindable.
-func (form *FormData) mustValue(key string, target interface{}, defaultValue interface{}) *FormData {
+func (form *FormData) mustValue(key string, target any, defaultValue any) *FormData {
 	val, ok := form.values[key]
 
 	if !ok || val[0] == "" {
@@ -468,7 +468,7 @@ func (form *FormData) mustValue(key string, target interface{}, defaultValue int
 // populates an error if the value is empty or the "key" does not exist.
 // Currently, only the string, bool, int, float64 and time.Duration types are
 // bindable.
-func (form *FormData) mustMandatoryField(key string, target interface{}) *FormData {
+func (form *FormData) mustMandatoryField(key string, target any) *FormData {
 	val, ok := form.values[key]
 
 	if !ok || val[0] == "" {
@@ -487,7 +487,7 @@ func (form *FormData) mustMandatoryField(key string, target interface{}) *FormDa
 // mustAssign parses the string value and tries to convert it to the target
 // interface real type. Currently, only the string, bool, int, float64 and
 // time.Duration types are bindable.
-func (form *FormData) mustAssign(key, value string, target interface{}) *FormData {
+func (form *FormData) mustAssign(key, value string, target any) *FormData {
 	var err error
 
 	switch t := (target).(type) {

pkg/modules/chromium/browser.go

@@ -288,7 +288,7 @@ func (b *chromiumBrowser) pdf(ctx context.Context, logger *zap.Logger, url, outp
 		navigateActionFunc(logger, url, options.SkipNetworkIdleEvent),
 		hideDefaultWhiteBackgroundActionFunc(logger, options.OmitBackground, options.PrintBackground),
 		forceExactColorsActionFunc(logger, options.PrintBackground),
-		emulateMediaTypeActionFunc(logger, options.EmulatedMediaType),
+		emulateMediaTypeActionFunc(logger, options.EmulatedMediaType, options.EmulatedMediaFeatures),
 		waitForExpressionBeforePrintActionFunc(logger, b.arguments.disableJavaScript, options.WaitForExpression),
 		waitForSelectorVisibleBeforePrintActionFunc(logger, options.WaitForSelector),
 		waitDelayBeforePrintActionFunc(logger, b.arguments.disableJavaScript, options.WaitDelay),
@@ -314,7 +314,7 @@ func (b *chromiumBrowser) screenshot(ctx context.Context, logger *zap.Logger, ur
 		navigateActionFunc(logger, url, options.SkipNetworkIdleEvent),
 		hideDefaultWhiteBackgroundActionFunc(logger, options.OmitBackground, true),
 		forceExactColorsActionFunc(logger, true),
-		emulateMediaTypeActionFunc(logger, options.EmulatedMediaType),
+		emulateMediaTypeActionFunc(logger, options.EmulatedMediaType, options.EmulatedMediaFeatures),
 		waitForExpressionBeforePrintActionFunc(logger, b.arguments.disableJavaScript, options.WaitForExpression),
 		waitForSelectorVisibleBeforePrintActionFunc(logger, options.WaitForSelector),
 		waitDelayBeforePrintActionFunc(logger, b.arguments.disableJavaScript, options.WaitDelay),

pkg/modules/chromium/chromium.go

@@ -86,9 +86,10 @@ var (
 // Chromium is a module that provides both an [Api] and routes for converting
 // an HTML document to PDF.
 type Chromium struct {
-	autoStart     bool
+	autoStart      bool
-	disableRoutes bool
+	disableRoutes  bool
-	args          browserArguments
+	maxConcurrency int64
+	args           browserArguments
 
 	logger     *zap.Logger
 	browser    browser
@@ -164,11 +165,28 @@ type Options struct {
 	// "print".
 	EmulatedMediaType string
 
+	// EmulatedMediaFeatures are the media features to emulate, e.g.,
+	// [{"name": "prefers-color-scheme", "value": "dark"}].
+	EmulatedMediaFeatures []EmulatedMediaFeature
+
 	// OmitBackground hides the default white background and allows generating
 	// PDFs with transparency.
 	OmitBackground bool
 }
 
+// EmulatedMediaFeature gathers the available entries for emulating a media
+// feature.
+type EmulatedMediaFeature struct {
+	// Name is the media feature name (e.g., "prefers-color-scheme",
+	// "prefers-reduced-motion").
+	// Required.
+	Name string `json:"name"`
+
+	// Value is the media feature value (e.g., "dark", "reduce").
+	// Required.
+	Value string `json:"value"`
+}
+
 // DefaultOptions returns the default values for Options.
 func DefaultOptions() Options {
 	return Options{
@@ -186,6 +204,7 @@ func DefaultOptions() Options {
 		UserAgent:                       "",
 		ExtraHttpHeaders:                nil,
 		EmulatedMediaType:               "",
+		EmulatedMediaFeatures:           nil,
 		OmitBackground:                  false,
 	}
 }
@@ -391,8 +410,9 @@ func (mod *Chromium) Descriptor() gotenberg.ModuleDescriptor {
 		ID: "chromium",
 		FlagSet: func() *flag.FlagSet {
 			fs := flag.NewFlagSet("chromium", flag.ExitOnError)
-			fs.Int64("chromium-restart-after", 10, "Number of conversions after which Chromium will automatically restart. Set to 0 to disable this feature")
+			fs.Int64("chromium-restart-after", 100, "Number of conversions after which Chromium will automatically restart. Set to 0 to disable this feature")
 			fs.Int64("chromium-max-queue-size", 0, "Maximum request queue size for Chromium. Set to 0 to disable this feature")
+			fs.Int64("chromium-max-concurrency", 6, "Maximum number of concurrent conversions. Chromium supports up to 6")
 			fs.Bool("chromium-auto-start", false, "Automatically launch Chromium upon initialization if set to true; otherwise, Chromium will start at the time of the first conversion")
 			fs.Duration("chromium-start-timeout", time.Duration(20)*time.Second, "Maximum duration to wait for Chromium to start or restart")
 			fs.Bool("chromium-allow-insecure-localhost", false, "Ignore TLS/SSL errors on localhost")
@@ -426,6 +446,7 @@ func (mod *Chromium) Provision(ctx *gotenberg.Context) error {
 	flags := ctx.ParsedFlags()
 	mod.autoStart = flags.MustBool("chromium-auto-start")
 	mod.disableRoutes = flags.MustBool("chromium-disable-routes")
+	mod.maxConcurrency = flags.MustInt64("chromium-max-concurrency")
 
 	binPath, ok := os.LookupEnv("CHROMIUM_BIN_PATH")
 	if !ok {
@@ -468,7 +489,7 @@ func (mod *Chromium) Provision(ctx *gotenberg.Context) error {
 
 	// Process.
 	mod.browser = newChromiumBrowser(mod.args)
-	mod.supervisor = gotenberg.NewProcessSupervisor(mod.logger, mod.browser, flags.MustInt64("chromium-restart-after"), flags.MustInt64("chromium-max-queue-size"))
+	mod.supervisor = gotenberg.NewProcessSupervisor(mod.logger, mod.browser, flags.MustInt64("chromium-restart-after"), flags.MustInt64("chromium-max-queue-size"), mod.maxConcurrency)
 
 	// PDF Engine.
 	provider, err := ctx.Module(new(gotenberg.PdfEngineProvider))
@@ -486,6 +507,10 @@ func (mod *Chromium) Provision(ctx *gotenberg.Context) error {
 
 // Validate validates the module properties.
 func (mod *Chromium) Validate() error {
+	if mod.maxConcurrency < 1 || mod.maxConcurrency > 6 {
+		return fmt.Errorf("chromium-max-concurrency must be between 1 and 6, got %d", mod.maxConcurrency)
+	}
+
 	_, err := os.Stat(mod.args.binPath)
 	if os.IsNotExist(err) {
 		return fmt.Errorf("chromium binary path does not exist: %w", err)
@@ -540,8 +565,8 @@ func (mod *Chromium) Stop(ctx context.Context) error {
 }
 
 // Debug returns additional debug data.
-func (mod *Chromium) Debug() map[string]interface{} {
+func (mod *Chromium) Debug() map[string]any {
-	debug := make(map[string]interface{})
+	debug := make(map[string]any)
 
 	cmd := exec.Command(mod.args.binPath, "--version") //nolint:gosec
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}

pkg/modules/chromium/debug.go

@@ -21,7 +21,7 @@ func (debug *debugLogger) Write(p []byte) (n int, err error) {
 }
 
 // Printf logs a debug message.
-func (debug *debugLogger) Printf(format string, v ...interface{}) {
+func (debug *debugLogger) Printf(format string, v ...any) {
 	debug.logger.Debug(fmt.Sprintf(format, v...))
 }
 

pkg/modules/chromium/events.go

@@ -39,7 +39,7 @@ func listenForEventRequestPaused(ctx context.Context, logger *zap.Logger, option
 		logger.Debug(fmt.Sprintf("extra HTTP headers: %+v", options.extraHttpHeaders))
 	}
 
-	chromedp.ListenTarget(ctx, func(ev interface{}) {
+	chromedp.ListenTarget(ctx, func(ev any) {
 		switch e := ev.(type) {
 		case *fetch.EventRequestPaused:
 			go func() {
@@ -176,7 +176,7 @@ func listenForEventResponseReceived(
 		}
 	}
 
-	chromedp.ListenTarget(ctx, func(ev interface{}) {
+	chromedp.ListenTarget(ctx, func(ev any) {
 		switch ev := ev.(type) {
 		case *network.EventResponseReceived:
 			if ev.Response.URL == options.mainPageUrl {
@@ -299,7 +299,7 @@ type eventLoadingFailedOptions struct {
 // https://github.com/gotenberg/gotenberg/issues/959.
 // https://github.com/gotenberg/gotenberg/issues/1021.
 func listenForEventLoadingFailed(ctx context.Context, logger *zap.Logger, options eventLoadingFailedOptions) {
-	chromedp.ListenTarget(ctx, func(ev interface{}) {
+	chromedp.ListenTarget(ctx, func(ev any) {
 		switch ev := ev.(type) {
 		case *network.EventLoadingFailed:
 			logger.Debug(fmt.Sprintf("event EventLoadingFailed fired: %+v", ev.ErrorText))
@@ -355,7 +355,7 @@ func listenForEventLoadingFailed(ctx context.Context, logger *zap.Logger, option
 // appends those exceptions to the given error pointer.
 // See https://github.com/gotenberg/gotenberg/issues/262.
 func listenForEventExceptionThrown(ctx context.Context, logger *zap.Logger, consoleExceptions *error, consoleExceptionsMu *sync.RWMutex) {
-	chromedp.ListenTarget(ctx, func(ev interface{}) {
+	chromedp.ListenTarget(ctx, func(ev any) {
 		switch ev := ev.(type) {
 		case *runtime.EventExceptionThrown:
 			logger.Debug(fmt.Sprintf("event EventExceptionThrown fired: %+v", ev.ExceptionDetails))
@@ -374,7 +374,7 @@ func waitForEventDomContentEventFired(ctx context.Context, logger *zap.Logger) f
 	return func() error {
 		ch := make(chan struct{})
 		cctx, cancel := context.WithCancel(ctx)
-		chromedp.ListenTarget(cctx, func(ev interface{}) {
+		chromedp.ListenTarget(cctx, func(ev any) {
 			switch ev.(type) {
 			case *page.EventDomContentEventFired:
 				cancel()
@@ -398,7 +398,7 @@ func waitForEventLoadEventFired(ctx context.Context, logger *zap.Logger) func()
 	return func() error {
 		ch := make(chan struct{})
 		cctx, cancel := context.WithCancel(ctx)
-		chromedp.ListenTarget(cctx, func(ev interface{}) {
+		chromedp.ListenTarget(cctx, func(ev any) {
 			switch ev.(type) {
 			case *page.EventLoadEventFired:
 				cancel()
@@ -422,7 +422,7 @@ func waitForEventNetworkIdle(ctx context.Context, logger *zap.Logger) func() err
 	return func() error {
 		ch := make(chan struct{})
 		cctx, cancel := context.WithCancel(ctx)
-		chromedp.ListenTarget(cctx, func(ev interface{}) {
+		chromedp.ListenTarget(cctx, func(ev any) {
 			switch e := ev.(type) {
 			case *page.EventLifecycleEvent:
 				if e.Name == "networkIdle" {
@@ -448,7 +448,7 @@ func waitForEventLoadingFinished(ctx context.Context, logger *zap.Logger) func()
 	return func() error {
 		ch := make(chan struct{})
 		cctx, cancel := context.WithCancel(ctx)
-		chromedp.ListenTarget(cctx, func(ev interface{}) {
+		chromedp.ListenTarget(cctx, func(ev any) {
 			switch ev.(type) {
 			case *network.EventLoadingFinished:
 				cancel()

pkg/modules/chromium/routes.go

@@ -39,6 +39,7 @@ var sameSiteRegexp = regexp2.MustCompile(
 //   - ignoreResourceHttpStatusDomains: []string
 //   - cookies: []Cookie
 //   - extraHttpHeaders: map[string]string
+//   - emulatedMediaFeatures: map[string]string
 //
 // Domain filtering only applies to resource checks triggered by
 // "failOnResourceHttpStatusCodes".
@@ -60,6 +61,7 @@ func FormDataChromiumOptions(ctx *api.Context) (*api.FormData, Options) {
 		userAgent                       string
 		extraHttpHeaders                []ExtraHttpHeader
 		emulatedMediaType               string
+		emulatedMediaFeatures           []EmulatedMediaFeature
 		omitBackground                  bool
 	)
 
@@ -170,8 +172,8 @@ func FormDataChromiumOptions(ctx *api.Context) (*api.FormData, Options) {
 				var valueTokens []string
 				var invalidScopeToken bool
 
-				tokens := strings.Split(v, ";")
+				tokens := strings.SplitSeq(v, ";")
-				for _, token := range tokens {
+				for token := range tokens {
 					if strings.HasPrefix(strings.ToLower(strings.TrimSpace(token)), "scope") {
 						tokenNoSpaces := strings.Join(strings.Fields(token), "")
 						parts := strings.SplitN(tokenNoSpaces, "=", 2)
@@ -227,6 +229,27 @@ func FormDataChromiumOptions(ctx *api.Context) (*api.FormData, Options) {
 
 			return nil
 		}).
+		Custom("emulatedMediaFeatures", func(value string) error {
+			if value == "" {
+				emulatedMediaFeatures = defaultOptions.EmulatedMediaFeatures
+				return nil
+			}
+
+			var features map[string]string
+			err := json.Unmarshal([]byte(value), &features)
+			if err != nil {
+				return fmt.Errorf("unmarshal emulatedMediaFeatures: %w", err)
+			}
+
+			for k, v := range features {
+				emulatedMediaFeatures = append(emulatedMediaFeatures, EmulatedMediaFeature{
+					Name:  k,
+					Value: v,
+				})
+			}
+
+			return err
+		}).
 		Bool("omitBackground", &omitBackground, defaultOptions.OmitBackground)
 
 	options := Options{
@@ -244,6 +267,7 @@ func FormDataChromiumOptions(ctx *api.Context) (*api.FormData, Options) {
 		UserAgent:                       userAgent,
 		ExtraHttpHeaders:                extraHttpHeaders,
 		EmulatedMediaType:               emulatedMediaType,
+		EmulatedMediaFeatures:           emulatedMediaFeatures,
 		OmitBackground:                  omitBackground,
 	}
 
@@ -662,7 +686,7 @@ func markdownToHtml(ctx *api.Context, inputPath string, markdownPaths []string)
 	return fmt.Sprintf("file://%s", inputPath), nil
 }
 
-func convertUrl(ctx *api.Context, chromium Api, engine gotenberg.PdfEngine, url string, options PdfOptions, mode gotenberg.SplitMode, pdfFormats gotenberg.PdfFormats, metadata map[string]interface{}, userPassword, ownerPassword string, embedPaths []string) error {
+func convertUrl(ctx *api.Context, chromium Api, engine gotenberg.PdfEngine, url string, options PdfOptions, mode gotenberg.SplitMode, pdfFormats gotenberg.PdfFormats, metadata map[string]any, userPassword, ownerPassword string, embedPaths []string) error {
 	outputPath := ctx.GeneratePath(".pdf")
 	// See https://github.com/gotenberg/gotenberg/issues/1130.
 	filename := ctx.OutputFilename(outputPath)

pkg/modules/chromium/stream.go

@@ -39,11 +39,9 @@ func (reader *streamReader) Read(p []byte) (n int, err error) {
 	// Chromium might have an off-by-one when deciding the maximum size (at
 	// least for base64 encoded data), usually it will overflow. We subtract
 	// one to make sure it fits into p.
-	size := len(p) - 1
+	size := max(len(p)-1,
-	if size < 1 {
 		// Safety-check to avoid crashing Chrome (e.g. via SetSize(-1)).
-		size = 1
+		1)
-	}
 
 	reply, err := reader.next(reader.pos, size)
 	if err != nil {

pkg/modules/chromium/tasks.go

@@ -423,26 +423,44 @@ func forceExactColorsActionFunc(logger *zap.Logger, printBackground bool) chrome
 	}
 }
 
-func emulateMediaTypeActionFunc(logger *zap.Logger, mediaType string) chromedp.ActionFunc {
+func emulateMediaTypeActionFunc(logger *zap.Logger, mediaType string, mediaFeatures []EmulatedMediaFeature) chromedp.ActionFunc {
 	return func(ctx context.Context) error {
-		if mediaType == "" {
+		if mediaType == "" && len(mediaFeatures) == 0 {
-			logger.Debug("no emulated media type")
+			logger.Debug("no emulated media type or features")
 			return nil
 		}
 
-		if mediaType != "screen" && mediaType != "print" {
+		if mediaType != "" && mediaType != "screen" && mediaType != "print" {
 			return fmt.Errorf("validate emulated media type '%s': %w", mediaType, ErrInvalidEmulatedMediaType)
 		}
 
-		logger.Debug(fmt.Sprintf("emulate media type '%s'", mediaType))
-
 		emulatedMedia := emulation.SetEmulatedMedia()
-		err := emulatedMedia.WithMedia(mediaType).Do(ctx)
+
+		if mediaType != "" {
+			logger.Debug(fmt.Sprintf("emulate media type '%s'", mediaType))
+			emulatedMedia = emulatedMedia.WithMedia(mediaType)
+		}
+
+		if len(mediaFeatures) > 0 {
+			logger.Debug(fmt.Sprintf("emulate media features %+v", mediaFeatures))
+
+			features := make([]*emulation.MediaFeature, len(mediaFeatures))
+			for i, f := range mediaFeatures {
+				features[i] = &emulation.MediaFeature{
+					Name:  f.Name,
+					Value: f.Value,
+				}
+			}
+
+			emulatedMedia = emulatedMedia.WithFeatures(features)
+		}
+
+		err := emulatedMedia.Do(ctx)
 		if err == nil {
 			return nil
 		}
 
-		return fmt.Errorf("emulate media type '%s': %w", mediaType, err)
+		return fmt.Errorf("emulate media: %w", err)
 	}
 }
 

pkg/modules/exiftool/exiftool.go

@@ -57,8 +57,8 @@ func (engine *ExifTool) Validate() error {
 }
 
 // Debug returns additional debug data.
-func (engine *ExifTool) Debug() map[string]interface{} {
+func (engine *ExifTool) Debug() map[string]any {
-	debug := make(map[string]interface{})
+	debug := make(map[string]any)
 
 	cmd := exec.Command(engine.binPath, "-ver") //nolint:gosec
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
@@ -94,7 +94,7 @@ func (engine *ExifTool) Convert(ctx context.Context, logger *zap.Logger, formats
 }
 
 // ReadMetadata extracts the metadata of a given PDF file.
-func (engine *ExifTool) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+func (engine *ExifTool) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
 	exifTool, err := exiftool.NewExiftool(exiftool.SetExiftoolBinaryPath(engine.binPath))
 	if err != nil {
 		return nil, fmt.Errorf("new ExifTool: %w", err)
@@ -116,7 +116,7 @@ func (engine *ExifTool) ReadMetadata(ctx context.Context, logger *zap.Logger, in
 }
 
 // WriteMetadata writes the metadata into a given PDF file.
-func (engine *ExifTool) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+func (engine *ExifTool) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 	exifTool, err := exiftool.NewExiftool(exiftool.SetExiftoolBinaryPath(engine.binPath))
 	if err != nil {
 		return fmt.Errorf("new ExifTool: %w", err)
@@ -134,13 +134,40 @@ func (engine *ExifTool) WriteMetadata(ctx context.Context, logger *zap.Logger, m
 		return fmt.Errorf("read metadata with ExitfTool: %w", fileMetadata[0].Err)
 	}
 
+	// Define a list of derived, system, or computed tags that ExifTool
+	// extracts but should never be written back. Writing these can break PDF/A
+	// compliance (e.g., PageCount -> prism:pageCount) or cause side effects
+	// (e.g., FileModifyDate).
+	derivedTags := []string{
+		"PageCount",           // Causes prism:pageCount injection
+		"Linearized",          // Computed status; writing it may invalidate structure
+		"PDFVersion",          // Header version; should not be manually forced via metadata
+		"MIMEType",            // Read-only derived
+		"FileType",            // Read-only derived
+		"FileTypeExtension",   // Read-only derived
+		"FileSize",            // System attribute
+		"FileModifyDate",      // System attribute
+		"FileAccessDate",      // System attribute
+		"FileInodeChangeDate", // System attribute
+		"FilePermissions",     // System attribute
+		"FileName",            // Writing this triggers a file rename in ExifTool
+		"Directory",           // System attribute
+		"ExifToolVersion",     // Tool metadata
+		"Error",               // Extraction error messages
+		"Warning",             // Extraction warning messages
+	}
+
+	for _, tag := range derivedTags {
+		delete(fileMetadata[0].Fields, tag)
+	}
+
 	for key, value := range metadata {
 		switch val := value.(type) {
 		case string:
 			fileMetadata[0].SetString(key, val)
 		case []string:
 			fileMetadata[0].SetStrings(key, val)
-		case []interface{}:
+		case []any:
 			// See https://github.com/gotenberg/gotenberg/issues/1048.
 			strs := make([]string, len(val))
 			for i, entry := range val {
@@ -148,7 +175,7 @@ func (engine *ExifTool) WriteMetadata(ctx context.Context, logger *zap.Logger, m
 					strs[i] = str
 					continue
 				}
-				return fmt.Errorf("write PDF metadata with ExifTool: %s %+v %s %w", key, val, reflect.TypeOf(val), gotenberg.ErrPdfEngineMetadataValueNotSupported)
+				return fmt.Errorf("write PDF metadata with ExifTool: %s %+v %s %w", key, val, reflect.TypeFor[[]any](), gotenberg.ErrPdfEngineMetadataValueNotSupported)
 			}
 			fileMetadata[0].SetStrings(key, strs)
 		case bool:

pkg/modules/libreoffice/api/api.go

@@ -54,7 +54,7 @@ type Api struct {
 // See: https://help.libreoffice.org/latest/en-US/text/shared/guide/pdf_params.html.
 type Options struct {
 	// Password specifies the password for opening the source file.
-	Password string
+	Password string // #nosec
 
 	// Landscape allows changing the orientation of the resulting PDF.
 	Landscape bool
@@ -253,7 +253,7 @@ func (a *Api) Provision(ctx *gotenberg.Context) error {
 
 	// Process.
 	a.libreOffice = newLibreOfficeProcess(a.args)
-	a.supervisor = gotenberg.NewProcessSupervisor(a.logger, a.libreOffice, flags.MustInt64("libreoffice-restart-after"), flags.MustInt64("libreoffice-max-queue-size"))
+	a.supervisor = gotenberg.NewProcessSupervisor(a.logger, a.libreOffice, flags.MustInt64("libreoffice-restart-after"), flags.MustInt64("libreoffice-max-queue-size"), 1)
 
 	return nil
 }
@@ -316,8 +316,8 @@ func (a *Api) Stop(ctx context.Context) error {
 }
 
 // Debug returns additional debug data.
-func (a *Api) Debug() map[string]interface{} {
+func (a *Api) Debug() map[string]any {
-	debug := make(map[string]interface{})
+	debug := make(map[string]any)
 
 	cmd := exec.Command(a.args.binPath, "--version") //nolint:gosec
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}

pkg/modules/libreoffice/pdfengine/pdfengine.go

@@ -82,12 +82,12 @@ func (engine *LibreOfficePdfEngine) Convert(ctx context.Context, logger *zap.Log
 }
 
 // ReadMetadata is not available in this implementation.
-func (engine *LibreOfficePdfEngine) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+func (engine *LibreOfficePdfEngine) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
 	return nil, fmt.Errorf("read PDF metadata with LibreOffice: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
 // WriteMetadata is not available in this implementation.
-func (engine *LibreOfficePdfEngine) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+func (engine *LibreOfficePdfEngine) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 	return fmt.Errorf("write PDF metadata with LibreOffice: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 

pkg/modules/logging/logging.go

@@ -177,7 +177,7 @@ func newLogLevel(level string) (zapcore.Level, error) {
 }
 
 func newLogEncoder(format string, gcpFields bool) (zapcore.Encoder, error) {
-	isTerminal := term.IsTerminal(int(os.Stdout.Fd()))
+	isTerminal := term.IsTerminal(int(os.Stdout.Fd())) // #nosec
 	encCfg := zap.NewProductionEncoderConfig()
 
 	// Normalize the log format based on the output device.

pkg/modules/pdfcpu/pdfcpu.go

@@ -57,8 +57,8 @@ func (engine *PdfCpu) Validate() error {
 }
 
 // Debug returns additional debug data.
-func (engine *PdfCpu) Debug() map[string]interface{} {
+func (engine *PdfCpu) Debug() map[string]any {
-	debug := make(map[string]interface{})
+	debug := make(map[string]any)
 
 	cmd := exec.Command(engine.binPath, "version") //nolint:gosec
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
@@ -71,10 +71,10 @@ func (engine *PdfCpu) Debug() map[string]interface{} {
 
 	debug["version"] = "Unable to determine pdfcpu version"
 
-	lines := strings.Split(string(output), "\n")
+	lines := strings.SplitSeq(string(output), "\n")
-	for _, line := range lines {
+	for line := range lines {
-		if strings.HasPrefix(line, "pdfcpu:") {
+		if after, ok := strings.CutPrefix(line, "pdfcpu:"); ok {
-			debug["version"] = strings.TrimSpace(strings.TrimPrefix(line, "pdfcpu:"))
+			debug["version"] = strings.TrimSpace(after)
 			break
 		}
 	}
@@ -84,7 +84,7 @@ func (engine *PdfCpu) Debug() map[string]interface{} {
 
 // Merge combines multiple PDFs into a single PDF.
 func (engine *PdfCpu) Merge(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error {
-	var args []string
+	args := make([]string, 0, 2+len(inputPaths))
 	args = append(args, "merge", outputPath)
 	args = append(args, inputPaths...)
 
@@ -162,12 +162,12 @@ func (engine *PdfCpu) Convert(ctx context.Context, logger *zap.Logger, formats g
 }
 
 // ReadMetadata is not available in this implementation.
-func (engine *PdfCpu) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+func (engine *PdfCpu) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
 	return nil, fmt.Errorf("read PDF metadata with pdfcpu: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
 // WriteMetadata is not available in this implementation.
-func (engine *PdfCpu) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+func (engine *PdfCpu) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 	return fmt.Errorf("write PDF metadata with pdfcpu: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
@@ -180,10 +180,8 @@ func (engine *PdfCpu) EmbedFiles(ctx context.Context, logger *zap.Logger, filePa
 
 	logger.Debug(fmt.Sprintf("embedding %d file(s) to %s: %v", len(filePaths), inputPath, filePaths))
 
-	args := []string{
+	args := make([]string, 0, 3+len(filePaths))
-		"attachments", "add",
+	args = append(args, "attachments", "add", inputPath)
-		inputPath,
-	}
 	args = append(args, filePaths...)
 
 	cmd, err := gotenberg.CommandContext(ctx, logger, engine.binPath, args...)
@@ -209,7 +207,7 @@ func (engine *PdfCpu) Encrypt(ctx context.Context, logger *zap.Logger, inputPath
 		ownerPassword = userPassword
 	}
 
-	var args []string
+	args := make([]string, 0, 11)
 	args = append(args, "encrypt")
 	args = append(args, "-mode", "aes")
 	args = append(args, "-upw", userPassword)

pkg/modules/pdfengines/multi.go

@@ -156,13 +156,13 @@ func (multi *multiPdfEngines) Convert(ctx context.Context, logger *zap.Logger, f
 }
 
 type readMetadataResult struct {
-	metadata map[string]interface{}
+	metadata map[string]any
 	err      error
 }
 
 // ReadMetadata extracts metadata from a PDF file using the first available
 // engine that supports metadata reading.
-func (multi *multiPdfEngines) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+func (multi *multiPdfEngines) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
 	var err error
 	var mu sync.Mutex // to safely append errors.
 
@@ -193,7 +193,7 @@ func (multi *multiPdfEngines) ReadMetadata(ctx context.Context, logger *zap.Logg
 
 // WriteMetadata embeds metadata into a PDF file using the first available
 // engine that supports metadata writing.
-func (multi *multiPdfEngines) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+func (multi *multiPdfEngines) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 	var err error
 	errChan := make(chan error, 1)
 

pkg/modules/pdfengines/multi_test.go

@@ -479,8 +479,8 @@ func TestMultiPdfEngines_ReadMetadata(t *testing.T) {
 			engine: &multiPdfEngines{
 				readMetadataEngines: []gotenberg.PdfEngine{
 					&gotenberg.PdfEngineMock{
-						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
-							return make(map[string]interface{}), nil
+							return make(map[string]any), nil
 						},
 					},
 				},
@@ -492,13 +492,13 @@ func TestMultiPdfEngines_ReadMetadata(t *testing.T) {
 			engine: &multiPdfEngines{
 				readMetadataEngines: []gotenberg.PdfEngine{
 					&gotenberg.PdfEngineMock{
-						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
 							return nil, errors.New("foo")
 						},
 					},
 					&gotenberg.PdfEngineMock{
-						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
-							return make(map[string]interface{}), nil
+							return make(map[string]any), nil
 						},
 					},
 				},
@@ -510,12 +510,12 @@ func TestMultiPdfEngines_ReadMetadata(t *testing.T) {
 			engine: &multiPdfEngines{
 				readMetadataEngines: []gotenberg.PdfEngine{
 					&gotenberg.PdfEngineMock{
-						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
 							return nil, errors.New("foo")
 						},
 					},
 					&gotenberg.PdfEngineMock{
-						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
 							return nil, errors.New("foo")
 						},
 					},
@@ -529,8 +529,8 @@ func TestMultiPdfEngines_ReadMetadata(t *testing.T) {
 			engine: &multiPdfEngines{
 				readMetadataEngines: []gotenberg.PdfEngine{
 					&gotenberg.PdfEngineMock{
-						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+						ReadMetadataMock: func(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
-							return make(map[string]interface{}), nil
+							return make(map[string]any), nil
 						},
 					},
 				},
@@ -570,7 +570,7 @@ func TestMultiPdfEngines_WriteMetadata(t *testing.T) {
 			engine: &multiPdfEngines{
 				writeMetadataEngines: []gotenberg.PdfEngine{
 					&gotenberg.PdfEngineMock{
-						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 							return nil
 						},
 					},
@@ -583,12 +583,12 @@ func TestMultiPdfEngines_WriteMetadata(t *testing.T) {
 			engine: &multiPdfEngines{
 				writeMetadataEngines: []gotenberg.PdfEngine{
 					&gotenberg.PdfEngineMock{
-						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 							return errors.New("foo")
 						},
 					},
 					&gotenberg.PdfEngineMock{
-						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 							return nil
 						},
 					},
@@ -601,12 +601,12 @@ func TestMultiPdfEngines_WriteMetadata(t *testing.T) {
 			engine: &multiPdfEngines{
 				writeMetadataEngines: []gotenberg.PdfEngine{
 					&gotenberg.PdfEngineMock{
-						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 							return errors.New("foo")
 						},
 					},
 					&gotenberg.PdfEngineMock{
-						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 							return errors.New("foo")
 						},
 					},
@@ -620,7 +620,7 @@ func TestMultiPdfEngines_WriteMetadata(t *testing.T) {
 			engine: &multiPdfEngines{
 				writeMetadataEngines: []gotenberg.PdfEngine{
 					&gotenberg.PdfEngineMock{
-						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+						WriteMetadataMock: func(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 							return nil
 						},
 					},

pkg/modules/pdfengines/pdfengines.go

@@ -3,6 +3,7 @@ package pdfengines
 import (
 	"errors"
 	"fmt"
+	"slices"
 	"strings"
 
 	flag "github.com/spf13/pflag"
@@ -179,13 +180,7 @@ func (mod *PdfEngines) Validate() error {
 				continue
 			}
 
-			alreadyInSlice := false
+			alreadyInSlice := slices.Contains(nonExistingEngines, name)
-			for _, engine := range nonExistingEngines {
-				if engine == name {
-					alreadyInSlice = true
-					break
-				}
-			}
 
 			if !alreadyInSlice {
 				nonExistingEngines = append(nonExistingEngines, name)

pkg/modules/pdfengines/routes.go

@@ -102,8 +102,8 @@ func FormDataPdfFormats(form *api.FormData) gotenberg.PdfFormats {
 }
 
 // FormDataPdfMetadata creates metadata object from the form data.
-func FormDataPdfMetadata(form *api.FormData, mandatory bool) map[string]interface{} {
+func FormDataPdfMetadata(form *api.FormData, mandatory bool) map[string]any {
-	var metadata map[string]interface{}
+	var metadata map[string]any
 
 	metadataFunc := func(value string) error {
 		if len(value) > 0 {
@@ -239,7 +239,7 @@ func ConvertStub(ctx *api.Context, engine gotenberg.PdfEngine, formats gotenberg
 
 // WriteMetadataStub writes the metadata into PDF files. If no metadata, it
 // does nothing.
-func WriteMetadataStub(ctx *api.Context, engine gotenberg.PdfEngine, metadata map[string]interface{}, inputPaths []string) error {
+func WriteMetadataStub(ctx *api.Context, engine gotenberg.PdfEngine, metadata map[string]any, inputPaths []string) error {
 	if len(metadata) == 0 {
 		return nil
 	}
@@ -558,7 +558,7 @@ func readMetadataRoute(engine gotenberg.PdfEngine) api.Route {
 				return fmt.Errorf("validate form data: %w", err)
 			}
 
-			res := make(map[string]map[string]interface{}, len(inputPaths))
+			res := make(map[string]map[string]any, len(inputPaths))
 			for _, inputPath := range inputPaths {
 				metadata, err := engine.ReadMetadata(ctx, ctx.Log(), inputPath)
 				if err != nil {

pkg/modules/pdftk/pdftk.go

@@ -56,8 +56,8 @@ func (engine *PdfTk) Validate() error {
 }
 
 // Debug returns additional debug data.
-func (engine *PdfTk) Debug() map[string]interface{} {
+func (engine *PdfTk) Debug() map[string]any {
-	debug := make(map[string]interface{})
+	debug := make(map[string]any)
 
 	cmd := exec.Command(engine.binPath, "--version") //nolint:gosec
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
@@ -108,7 +108,7 @@ func (engine *PdfTk) Split(ctx context.Context, logger *zap.Logger, mode gotenbe
 
 // Merge combines multiple PDFs into a single PDF.
 func (engine *PdfTk) Merge(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error {
-	var args []string
+	args := make([]string, 0, 3+len(inputPaths))
 	args = append(args, inputPaths...)
 	args = append(args, "cat", "output", outputPath)
 
@@ -136,12 +136,12 @@ func (engine *PdfTk) Convert(ctx context.Context, logger *zap.Logger, formats go
 }
 
 // ReadMetadata is not available in this implementation.
-func (engine *PdfTk) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+func (engine *PdfTk) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
 	return nil, fmt.Errorf("read PDF metadata with PDFtk: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
 // WriteMetadata is not available in this implementation.
-func (engine *PdfTk) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+func (engine *PdfTk) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 	return fmt.Errorf("write PDF metadata with PDFtk: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
@@ -158,7 +158,7 @@ func (engine *PdfTk) Encrypt(ctx context.Context, logger *zap.Logger, inputPath,
 	// Create a temp output file in the same directory.
 	tmpPath := inputPath + ".tmp"
 
-	var args []string
+	args := make([]string, 0, 8)
 	args = append(args, inputPath)
 	args = append(args, "output", tmpPath)
 	args = append(args, "encrypt_128bit")

pkg/modules/qpdf/qpdf.go

@@ -59,8 +59,8 @@ func (engine *QPdf) Validate() error {
 }
 
 // Debug returns additional debug data.
-func (engine *QPdf) Debug() map[string]interface{} {
+func (engine *QPdf) Debug() map[string]any {
-	debug := make(map[string]interface{})
+	debug := make(map[string]any)
 
 	cmd := exec.Command(engine.binPath, "--version") //nolint:gosec
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
@@ -114,7 +114,7 @@ func (engine *QPdf) Split(ctx context.Context, logger *zap.Logger, mode gotenber
 
 // Merge combines multiple PDFs into a single PDF.
 func (engine *QPdf) Merge(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error {
-	var args []string
+	args := make([]string, 0, 4+len(engine.globalArgs)+len(inputPaths))
 	args = append(args, "--empty")
 	args = append(args, engine.globalArgs...)
 	args = append(args, "--pages")
@@ -137,7 +137,7 @@ func (engine *QPdf) Merge(ctx context.Context, logger *zap.Logger, inputPaths []
 // Flatten merges annotation appearances with page content, deleting the
 // original annotations.
 func (engine *QPdf) Flatten(ctx context.Context, logger *zap.Logger, inputPath string) error {
-	var args []string
+	args := make([]string, 0, 4+len(engine.globalArgs))
 	args = append(args, inputPath)
 	args = append(args, "--generate-appearances")
 	args = append(args, "--flatten-annotations=all")
@@ -163,12 +163,12 @@ func (engine *QPdf) Convert(ctx context.Context, logger *zap.Logger, formats got
 }
 
 // ReadMetadata is not available in this implementation.
-func (engine *QPdf) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]interface{}, error) {
+func (engine *QPdf) ReadMetadata(ctx context.Context, logger *zap.Logger, inputPath string) (map[string]any, error) {
 	return nil, fmt.Errorf("read PDF metadata with QPDF: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
 // WriteMetadata is not available in this implementation.
-func (engine *QPdf) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]interface{}, inputPath string) error {
+func (engine *QPdf) WriteMetadata(ctx context.Context, logger *zap.Logger, metadata map[string]any, inputPath string) error {
 	return fmt.Errorf("write PDF metadata with QPDF: %w", gotenberg.ErrPdfEngineMethodNotSupported)
 }
 
@@ -182,7 +182,7 @@ func (engine *QPdf) Encrypt(ctx context.Context, logger *zap.Logger, inputPath,
 		ownerPassword = userPassword
 	}
 
-	var args []string
+	args := make([]string, 0, 7+len(engine.globalArgs))
 	args = append(args, inputPath)
 	args = append(args, engine.globalArgs...)
 	args = append(args, "--replace-input")

test/integration/features/chromium_concurrent.feature

@@ -0,0 +1,20 @@
+@chromium
+@chromium-concurrent
+Feature: Chromium concurrent conversions
+
+  Scenario: Concurrent HTML to PDF conversions with max concurrency 3
+    Given I have a Gotenberg container with the following environment variable(s):
+      | CHROMIUM_MAX_CONCURRENCY | 3 |
+    When I make 3 concurrent "POST" requests to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files | testdata/page-1-html/index.html | file |
+    Then all concurrent response status codes should be 200
+    Then all concurrent responses should have 1 PDF(s)
+
+  Scenario: Concurrent conversions exceeding restart-after limit
+    Given I have a Gotenberg container with the following environment variable(s):
+      | CHROMIUM_MAX_CONCURRENCY | 3 |
+      | CHROMIUM_RESTART_AFTER   | 5 |
+    When I make 10 concurrent "POST" requests to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files | testdata/page-1-html/index.html | file |
+    Then all concurrent response status codes should be 200
+    Then all concurrent responses should have 1 PDF(s)

test/integration/features/chromium_convert_html.feature

@@ -281,6 +281,82 @@ Feature: /forms/chromium/convert/html
       Emulated media type is 'print'.
       """
 
+  Scenario: POST /forms/chromium/convert/html (Emulated Media Features)
+    Given I have a default Gotenberg container
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files                     | testdata/feature-rich-html/index.html | file   |
+      | Gotenberg-Output-Filename | foo                                   | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | foo.pdf |
+    Then the "foo.pdf" PDF should have 1 page(s)
+    Then the "foo.pdf" PDF should NOT have the following content at page 1:
+      """
+      Prefers reduced motion.
+      """
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files                     | testdata/feature-rich-html/index.html | file   |
+      | emulatedMediaFeatures     | {"prefers-reduced-motion":"reduce"}   | field  |
+      | Gotenberg-Output-Filename | foo                                   | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | foo.pdf |
+    Then the "foo.pdf" PDF should have 1 page(s)
+    Then the "foo.pdf" PDF should have the following content at page 1:
+      """
+      Prefers reduced motion.
+      """
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files                     | testdata/feature-rich-html/index.html | file   |
+      | emulatedMediaType         | screen                                | field  |
+      | emulatedMediaFeatures     | {"prefers-reduced-motion":"reduce"}   | field  |
+      | Gotenberg-Output-Filename | foo                                   | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | foo.pdf |
+    Then the "foo.pdf" PDF should have 1 page(s)
+    Then the "foo.pdf" PDF should have the following content at page 1:
+      """
+      Emulated media type is 'screen'.
+      """
+    Then the "foo.pdf" PDF should have the following content at page 1:
+      """
+      Prefers reduced motion.
+      """
+    Then the "foo.pdf" PDF should NOT have the following content at page 1:
+      """
+      Emulated media type is 'print'.
+      """
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files                     | testdata/feature-rich-html/index.html | file   |
+      | emulatedMediaType         | print                                 | field  |
+      | emulatedMediaFeatures     | {"prefers-reduced-motion":"reduce"}   | field  |
+      | Gotenberg-Output-Filename | foo                                   | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | foo.pdf |
+    Then the "foo.pdf" PDF should have 1 page(s)
+    Then the "foo.pdf" PDF should have the following content at page 1:
+      """
+      Emulated media type is 'print'.
+      """
+    Then the "foo.pdf" PDF should have the following content at page 1:
+      """
+      Prefers reduced motion.
+      """
+    Then the "foo.pdf" PDF should NOT have the following content at page 1:
+      """
+      Emulated media type is 'screen'.
+      """
+
   Scenario: POST /forms/chromium/convert/html (Default Allow / Deny Lists)
     Given I have a default Gotenberg container
     When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
@@ -550,6 +626,15 @@ Feature: /forms/chromium/convert/html
       """
       Invalid form data: form field 'extraHttpHeaders' is invalid (got '{"foo":"bar;scope=*."}', resulting to invalid scope regex pattern for header 'foo': error parsing regexp: missing argument to repetition operator in `*.`)
       """
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
+      | files                 | testdata/page-1-html/index.html | file  |
+      | emulatedMediaFeatures | foo                             | field |
+    Then the response status code should be 400
+    Then the response header "Content-Type" should be "text/plain; charset=UTF-8"
+    Then the response body should match string:
+      """
+      Invalid form data: form field 'emulatedMediaFeatures' is invalid (got 'foo', resulting to unmarshal emulatedMediaFeatures: invalid character 'o' in literal false (expecting 'a'))
+      """
     When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/html" endpoint with the following form data and header(s):
       | files     | testdata/page-1-html/index.html | file  |
       | splitMode | foo                             | field |

test/integration/features/chromium_convert_url.feature

@@ -346,6 +346,86 @@ Feature: /forms/chromium/convert/url
       Emulated media type is 'print'.
       """
 
+  Scenario: POST /forms/chromium/convert/url (Emulated Media Features)
+    Given I have a default Gotenberg container
+    Given I have a static server
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/url" endpoint with the following form data and header(s):
+      | url                       | http://host.docker.internal:%d/html/testdata/feature-rich-html-remote/index.html | field  |
+      | Gotenberg-Output-Filename | foo                                                                              | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | foo.pdf |
+    Then the "foo.pdf" PDF should have 1 page(s)
+    Then the "foo.pdf" PDF should NOT have the following content at page 1:
+      """
+      Prefers reduced motion.
+      """
+    Given I have a static server
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/url" endpoint with the following form data and header(s):
+      | url                       | http://host.docker.internal:%d/html/testdata/feature-rich-html-remote/index.html | field  |
+      | emulatedMediaFeatures     | {"prefers-reduced-motion":"reduce"}                                              | field  |
+      | Gotenberg-Output-Filename | foo                                                                              | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | foo.pdf |
+    Then the "foo.pdf" PDF should have 1 page(s)
+    Then the "foo.pdf" PDF should have the following content at page 1:
+      """
+      Prefers reduced motion.
+      """
+    Given I have a static server
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/url" endpoint with the following form data and header(s):
+      | url                       | http://host.docker.internal:%d/html/testdata/feature-rich-html-remote/index.html | field  |
+      | emulatedMediaType         | screen                                                                           | field  |
+      | emulatedMediaFeatures     | {"prefers-reduced-motion":"reduce"}                                              | field  |
+      | Gotenberg-Output-Filename | foo                                                                              | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | foo.pdf |
+    Then the "foo.pdf" PDF should have 1 page(s)
+    Then the "foo.pdf" PDF should have the following content at page 1:
+      """
+      Emulated media type is 'screen'.
+      """
+    Then the "foo.pdf" PDF should have the following content at page 1:
+      """
+      Prefers reduced motion.
+      """
+    Then the "foo.pdf" PDF should NOT have the following content at page 1:
+      """
+      Emulated media type is 'print'.
+      """
+    Given I have a static server
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/url" endpoint with the following form data and header(s):
+      | url                       | http://host.docker.internal:%d/html/testdata/feature-rich-html-remote/index.html | field  |
+      | emulatedMediaType         | print                                                                            | field  |
+      | emulatedMediaFeatures     | {"prefers-reduced-motion":"reduce"}                                              | field  |
+      | Gotenberg-Output-Filename | foo                                                                              | header |
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/pdf"
+    Then there should be 1 PDF(s) in the response
+    Then there should be the following file(s) in the response:
+      | foo.pdf |
+    Then the "foo.pdf" PDF should have 1 page(s)
+    Then the "foo.pdf" PDF should have the following content at page 1:
+      """
+      Emulated media type is 'print'.
+      """
+    Then the "foo.pdf" PDF should have the following content at page 1:
+      """
+      Prefers reduced motion.
+      """
+    Then the "foo.pdf" PDF should NOT have the following content at page 1:
+      """
+      Emulated media type is 'screen'.
+      """
+
   Scenario: POST /forms/chromium/convert/url (Default Allow / Deny Lists)
     Given I have a default Gotenberg container
     Given I have a static server
@@ -627,6 +707,16 @@ Feature: /forms/chromium/convert/url
       Invalid form data: form field 'extraHttpHeaders' is invalid (got '{"foo":"bar;scope=*."}', resulting to invalid scope regex pattern for header 'foo': error parsing regexp: missing argument to repetition operator in `*.`)
       """
     Given I have a static server
+    When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/url" endpoint with the following form data and header(s):
+      | url                   | http://host.docker.internal:%d/html/testdata/page-1-html/index.html | field |
+      | emulatedMediaFeatures | foo                                                                 | field |
+    Then the response status code should be 400
+    Then the response header "Content-Type" should be "text/plain; charset=UTF-8"
+    Then the response body should match string:
+      """
+      Invalid form data: form field 'emulatedMediaFeatures' is invalid (got 'foo', resulting to unmarshal emulatedMediaFeatures: invalid character 'o' in literal false (expecting 'a'))
+      """
+    Given I have a static server
     When I make a "POST" request to Gotenberg at the "/forms/chromium/convert/url" endpoint with the following form data and header(s):
       | url       | http://host.docker.internal:%d/html/testdata/page-1-html/index.html | field |
       | splitMode | foo                                                                 | field |

test/integration/features/debug.feature

@@ -16,6 +16,127 @@ Feature: /debug
       """
       {
         "version": "{version}",
+        "timezone": "UTC",
+        "architecture": "ignore",
+        "modules": [
+          "api",
+          "chromium",
+          "exiftool",
+          "libreoffice",
+          "libreoffice-api",
+          "libreoffice-pdfengine",
+          "logging",
+          "pdfcpu",
+          "pdfengines",
+          "pdftk",
+          "prometheus",
+          "qpdf",
+          "webhook"
+        ],
+        "modules_additional_data": {
+          "chromium": {
+            "version": "ignore"
+          },
+          "exiftool": {
+            "version": "ignore"
+          },
+          "libreoffice-api": {
+            "version": "ignore"
+          },
+          "pdfcpu": {
+            "version": "ignore"
+          },
+          "pdftk": {
+            "version": "ignore"
+          },
+          "qpdf": {
+            "version": "ignore"
+          }
+        },
+        "flags": {
+          "api-bind-ip": "",
+          "api-body-limit": "",
+          "api-disable-download-from": "false",
+          "api-disable-health-check-logging": "false",
+          "api-download-from-allow-list": "",
+          "api-download-from-deny-list": "",
+          "api-download-from-max-retry": "4",
+          "api-enable-basic-auth": "false",
+          "api-enable-debug-route": "true",
+          "api-port": "3000",
+          "api-port-from-env": "",
+          "api-root-path": "/",
+          "api-start-timeout": "30s",
+          "api-timeout": "30s",
+          "api-tls-cert-file": "",
+          "api-tls-key-file": "",
+          "api-trace-header": "Gotenberg-Trace",
+          "chromium-allow-file-access-from-files": "false",
+          "chromium-allow-insecure-localhost": "false",
+          "chromium-allow-list": "",
+          "chromium-auto-start": "false",
+          "chromium-clear-cache": "false",
+          "chromium-clear-cookies": "false",
+          "chromium-deny-list": "^file:(?!//\\/tmp/).*",
+          "chromium-disable-javascript": "false",
+          "chromium-disable-routes": "false",
+          "chromium-disable-web-security": "false",
+          "chromium-host-resolver-rules": "",
+          "chromium-ignore-certificate-errors": "false",
+          "chromium-incognito": "false",
+          "chromium-max-concurrency": "6",
+          "chromium-max-queue-size": "0",
+          "chromium-proxy-server": "",
+          "chromium-restart-after": "100",
+          "chromium-start-timeout": "20s",
+          "gotenberg-build-debug-data": "true",
+          "gotenberg-graceful-shutdown-duration": "30s",
+          "libreoffice-auto-start": "false",
+          "libreoffice-disable-routes": "false",
+          "libreoffice-max-queue-size": "0",
+          "libreoffice-restart-after": "10",
+          "libreoffice-start-timeout": "20s",
+          "log-fields-prefix": "",
+          "log-format": "auto",
+          "log-level": "info",
+          "pdfengines-convert-engines": "[libreoffice-pdfengine]",
+          "pdfengines-disable-routes": "false",
+          "pdfengines-engines": "[]",
+          "pdfengines-flatten-engines": "[qpdf]",
+          "pdfengines-merge-engines": "[qpdf,pdfcpu,pdftk]",
+          "pdfengines-read-metadata-engines": "[exiftool]",
+          "pdfengines-split-engines": "[pdfcpu,qpdf,pdftk]",
+          "pdfengines-write-metadata-engines": "[exiftool]",
+          "prometheus-collect-interval": "1s",
+          "prometheus-disable-collect": "false",
+          "prometheus-disable-route-logging": "false",
+          "prometheus-namespace": "gotenberg",
+          "prometheus-metrics-path": "/prometheus/metrics",
+          "webhook-allow-list": "",
+          "webhook-client-timeout": "30s",
+          "webhook-deny-list": "",
+          "webhook-disable": "false",
+          "webhook-error-allow-list": "",
+          "webhook-error-deny-list": "",
+          "webhook-max-retry": "4",
+          "webhook-retry-max-wait": "30s",
+          "webhook-retry-min-wait": "1s"
+        }
+      }
+      """
+
+  Scenario: GET /debug (Environment based timezone)
+    Given I have a Gotenberg container with the following environment variable(s):
+      | API_ENABLE_DEBUG_ROUTE | true             |
+      | TZ                     | America/New_York |
+    When I make a "GET" request to Gotenberg at the "/debug" endpoint
+    Then the response status code should be 200
+    Then the response header "Content-Type" should be "application/json"
+    Then the response body should match JSON:
+      """
+      {
+        "version": "{version}",
+        "timezone": "America/New_York",
         "architecture": "ignore",
         "modules": [
           "api",
@@ -84,8 +205,9 @@ Feature: /debug
           "chromium-ignore-certificate-errors": "false",
           "chromium-incognito": "false",
           "chromium-max-queue-size": "0",
+          "chromium-max-concurrency": "6",
           "chromium-proxy-server": "",
-          "chromium-restart-after": "10",
+          "chromium-restart-after": "100",
           "chromium-start-timeout": "20s",
           "gotenberg-build-debug-data": "true",
           "gotenberg-graceful-shutdown-duration": "30s",
@@ -134,6 +256,7 @@ Feature: /debug
       """
       {
         "version": "",
+        "timezone": "",
         "architecture": "",
         "modules": null,
         "modules_additional_data": null,

test/integration/scenario/compare.go

@@ -5,11 +5,11 @@ import (
 	"reflect"
 )
 
-func compareJson(expected, actual interface{}) error {
+func compareJson(expected, actual any) error {
 	// Handle maps (JSON objects).
-	expectedMap, ok := expected.(map[string]interface{})
+	expectedMap, ok := expected.(map[string]any)
 	if ok {
-		actualMap, ok := actual.(map[string]interface{})
+		actualMap, ok := actual.(map[string]any)
 		if !ok {
 			return fmt.Errorf("expected an object, but actual is: %T", actual)
 		}
@@ -31,9 +31,9 @@ func compareJson(expected, actual interface{}) error {
 	}
 
 	// Handle slices (JSON arrays).
-	expectedSlice, ok := expected.([]interface{})
+	expectedSlice, ok := expected.([]any)
 	if ok {
-		actualSlice, ok := actual.([]interface{})
+		actualSlice, ok := actual.([]any)
 		if !ok {
 			return fmt.Errorf("expected an array, but actual is: %T", actual)
 		}

test/integration/scenario/containers.go

@@ -22,7 +22,7 @@ var (
 
 type noopLogger struct{}
 
-func (n *noopLogger) Printf(format string, v ...interface{}) {
+func (n *noopLogger) Printf(format string, v ...any) {
 	// NOOP
 }
 

test/integration/scenario/http.go

@@ -20,6 +20,7 @@ func doRequest(method, url string, headers map[string]string, body io.Reader) (*
 		req.Header.Set(header, value)
 	}
 
+	// #nosec
 	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		return nil, fmt.Errorf("send a request: %w", err)
@@ -74,6 +75,7 @@ func doFormDataRequest(method, url string, fields map[string]string, files map[s
 	}
 	req.Header.Set("Content-Type", writer.FormDataContentType())
 
+	// #nosec
 	resp, err := http.DefaultClient.Do(req)
 	if err != nil {
 		return nil, fmt.Errorf("send a request: %w", err)

test/integration/scenario/scenario.go

@@ -14,6 +14,7 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/cucumber/godog"
@@ -24,6 +25,7 @@ import (
 
 type scenario struct {
 	resp                      *httptest.ResponseRecorder
+	concurrentResps           []*httptest.ResponseRecorder
 	workdir                   string
 	gotenbergContainer        testcontainers.Container
 	gotenbergContainerNetwork *testcontainers.DockerNetwork
@@ -33,6 +35,7 @@ type scenario struct {
 
 func (s *scenario) reset(ctx context.Context) error {
 	s.resp = httptest.NewRecorder()
+	s.concurrentResps = nil
 
 	err := os.RemoveAll(s.workdir)
 	if err != nil {
@@ -281,6 +284,168 @@ func (s *scenario) iMakeARequestToGotenbergWithTheFollowingFormDataAndHeaders(ct
 	return nil
 }
 
+func (s *scenario) iMakeConcurrentRequestsToGotenberg(ctx context.Context, count int, method, endpoint string, dataTable *godog.Table) error {
+	if s.gotenbergContainer == nil {
+		return errors.New("no Gotenberg container")
+	}
+
+	fields := make(map[string]string)
+	files := make(map[string][]string)
+	headers := make(map[string]string)
+
+	for _, row := range dataTable.Rows {
+		name := row.Cells[0].Value
+		value := row.Cells[1].Value
+		kind := row.Cells[2].Value
+
+		switch kind {
+		case "field":
+			fields[name] = value
+		case "file":
+			wd, err := os.Getwd()
+			if err != nil {
+				return fmt.Errorf("get current directory: %w", err)
+			}
+			value = fmt.Sprintf("%s/%s", wd, value)
+			files[name] = append(files[name], value)
+		case "header":
+			headers[name] = value
+		default:
+			return fmt.Errorf("unexpected %q %q", kind, value)
+		}
+	}
+
+	base, err := containerHttpEndpoint(ctx, s.gotenbergContainer, "3000")
+	if err != nil {
+		return fmt.Errorf("get container HTTP endpoint: %w", err)
+	}
+
+	var (
+		mu sync.Mutex
+		wg sync.WaitGroup
+	)
+	s.concurrentResps = make([]*httptest.ResponseRecorder, 0, count)
+	errs := make([]error, 0)
+
+	for range count {
+		wg.Go(func() {
+			resp, reqErr := doFormDataRequest(method, fmt.Sprintf("%s%s", base, endpoint), fields, files, headers)
+			if reqErr != nil {
+				mu.Lock()
+				errs = append(errs, fmt.Errorf("do request: %w", reqErr))
+				mu.Unlock()
+				return
+			}
+			defer resp.Body.Close()
+
+			body, reqErr := io.ReadAll(resp.Body)
+			if reqErr != nil {
+				mu.Lock()
+				errs = append(errs, fmt.Errorf("read response body: %w", reqErr))
+				mu.Unlock()
+				return
+			}
+
+			rec := httptest.NewRecorder()
+			rec.Code = resp.StatusCode
+			for key, values := range resp.Header {
+				for _, v := range values {
+					rec.Header().Add(key, v)
+				}
+			}
+			_, _ = rec.Body.Write(body)
+
+			if resp.StatusCode == http.StatusOK {
+				cd := resp.Header.Get("Content-Disposition")
+				if cd != "" {
+					_, params, parseErr := mime.ParseMediaType(cd)
+					if parseErr == nil {
+						if filename, ok := params["filename"]; ok {
+							traceID := resp.Header.Get("Gotenberg-Trace")
+							dirPath := fmt.Sprintf("%s/%s", s.workdir, traceID)
+
+							mu.Lock()
+							mkErr := os.MkdirAll(dirPath, 0o755)
+							mu.Unlock()
+
+							if mkErr == nil {
+								fpath := fmt.Sprintf("%s/%s", dirPath, filename)
+								f, fErr := os.Create(fpath)
+								if fErr == nil {
+									_, _ = f.Write(body)
+									f.Close()
+								}
+							}
+						}
+					}
+				}
+			}
+
+			mu.Lock()
+			s.concurrentResps = append(s.concurrentResps, rec)
+			mu.Unlock()
+		})
+	}
+
+	wg.Wait()
+
+	if len(errs) > 0 {
+		return fmt.Errorf("concurrent requests failed: %v", errs)
+	}
+
+	return nil
+}
+
+func (s *scenario) allConcurrentResponseStatusCodesShouldBe(expected int) error {
+	if len(s.concurrentResps) == 0 {
+		return errors.New("no concurrent responses recorded")
+	}
+
+	for i, resp := range s.concurrentResps {
+		if resp.Code != expected {
+			return fmt.Errorf("concurrent response %d: expected status %d, got %d %q", i+1, expected, resp.Code, resp.Body.String())
+		}
+	}
+
+	return nil
+}
+
+func (s *scenario) allConcurrentResponsesShouldHavePdfs(expected int) error {
+	if len(s.concurrentResps) == 0 {
+		return errors.New("no concurrent responses recorded")
+	}
+
+	for i, resp := range s.concurrentResps {
+		traceID := resp.Header().Get("Gotenberg-Trace")
+		dirPath := fmt.Sprintf("%s/%s", s.workdir, traceID)
+
+		_, err := os.Stat(dirPath)
+		if os.IsNotExist(err) {
+			return fmt.Errorf("concurrent response %d: directory %q does not exist", i+1, dirPath)
+		}
+
+		var paths []string
+		err = filepath.Walk(dirPath, func(path string, info os.FileInfo, pathErr error) error {
+			if pathErr != nil {
+				return pathErr
+			}
+			if strings.EqualFold(filepath.Ext(info.Name()), ".pdf") {
+				paths = append(paths, path)
+			}
+			return nil
+		})
+		if err != nil {
+			return fmt.Errorf("concurrent response %d: walk %q: %w", i+1, dirPath, err)
+		}
+
+		if len(paths) != expected {
+			return fmt.Errorf("concurrent response %d: expected %d PDF(s), got %d", i+1, expected, len(paths))
+		}
+	}
+
+	return nil
+}
+
 func (s *scenario) iWaitForTheAsynchronousRequestToWebhook(ctx context.Context) error {
 	if s.server == nil {
 		return errors.New("server not initialized")
@@ -327,7 +492,7 @@ func (s *scenario) theGotenbergContainerShouldLogTheFollowingEntries(ctx context
 	}
 
 	var err error
-	for i := 0; i < 3; i++ {
+	for range 3 {
 		err = check()
 		if err != nil && !invert {
 			// We have to retry as not all logs may have been produced.
@@ -450,7 +615,7 @@ func (s *scenario) theBodyShouldMatchJSON(kind string, expectedDoc *godog.DocStr
 		body = s.server.bodyCopy
 	}
 
-	var expected, actual interface{}
+	var expected, actual any
 
 	content := strings.ReplaceAll(expectedDoc.Content, "{version}", GotenbergVersion)
 	err := json.Unmarshal([]byte(content), &expected)
@@ -965,9 +1130,12 @@ func InitializeScenario(ctx *godog.ScenarioContext) {
 	ctx.When(`^I make a "(GET|HEAD)" request to Gotenberg at the "([^"]*)" endpoint$`, s.iMakeARequestToGotenberg)
 	ctx.When(`^I make a "(GET|HEAD)" request to Gotenberg at the "([^"]*)" endpoint with the following header\(s\):$`, s.iMakeARequestToGotenbergWithTheFollowingHeaders)
 	ctx.When(`^I make a "(POST)" request to Gotenberg at the "([^"]*)" endpoint with the following form data and header\(s\):$`, s.iMakeARequestToGotenbergWithTheFollowingFormDataAndHeaders)
+	ctx.When(`^I make (\d+) concurrent "(POST)" requests to Gotenberg at the "([^"]*)" endpoint with the following form data and header\(s\):$`, s.iMakeConcurrentRequestsToGotenberg)
 	ctx.When(`^I wait for the asynchronous request to the webhook$`, s.iWaitForTheAsynchronousRequestToWebhook)
 	ctx.Then(`^the Gotenberg container (should|should NOT) log the following entries:$`, s.theGotenbergContainerShouldLogTheFollowingEntries)
 	ctx.Then(`^the response status code should be (\d+)$`, s.theResponseStatusCodeShouldBe)
+	ctx.Then(`^all concurrent response status codes should be (\d+)$`, s.allConcurrentResponseStatusCodesShouldBe)
+	ctx.Then(`^all concurrent responses should have (\d+) PDF\(s\)$`, s.allConcurrentResponsesShouldHavePdfs)
 	ctx.Then(`^the (response|webhook request|file request|server request) header "([^"]*)" should be "([^"]*)"$`, s.theHeaderValueShouldBe)
 	ctx.Then(`^the (response|webhook request|file request|server request) cookie "([^"]*)" should be "([^"]*)"$`, s.theCookieValueShouldBe)
 	ctx.Then(`^the (response|webhook request) body should match string:$`, s.theBodyShouldMatchString)

test/integration/scenario/server.go

@@ -79,12 +79,14 @@ func newServer(ctx context.Context, workdir string) (*server, error) {
 		}
 
 		dirPath := fmt.Sprintf("%s/%s", workdir, s.req.Header.Get("Gotenberg-Trace"))
+		// #nosec
 		err = os.MkdirAll(dirPath, 0o755)
 		if err != nil {
 			return webhookErr(fmt.Errorf("create working directory: %w", err))
 		}
 
 		fpath := fmt.Sprintf("%s/%s", dirPath, filename)
+		// #nosec
 		file, err := os.Create(fpath)
 		if err != nil {
 			return webhookErr(fmt.Errorf("create file %q: %w", fpath, err))

test/integration/testdata/feature-rich-html-remote/index.html

@@ -20,6 +20,14 @@
           display: none;
         }
       }
+      #reduced-motion {
+        display: none;
+      }
+      @media (prefers-reduced-motion: reduce) {
+        #reduced-motion {
+          display: block;
+        }
+      }
     </style>
   </head>
   <body>
@@ -29,6 +37,7 @@
     </p>
     <p id="print">Emulated media type is 'print'.</p>
     <p id="screen">Emulated media type is 'screen'.</p>
+    <p id="reduced-motion">Prefers reduced motion.</p>
     <p id="javascript" style="display: none">JavaScript is enabled.</p>
     <iframe src="file:///etc/passwd"></iframe>
 

test/integration/testdata/feature-rich-html/index.html

@@ -28,6 +28,14 @@
           display: none;
         }
       }
+      #reduced-motion {
+        display: none;
+      }
+      @media (prefers-reduced-motion: reduce) {
+        #reduced-motion {
+          display: block;
+        }
+      }
     </style>
   </head>
   <body>
@@ -37,6 +45,7 @@
     </p>
     <p id="print">Emulated media type is 'print'.</p>
     <p id="screen">Emulated media type is 'screen'.</p>
+    <p id="reduced-motion">Prefers reduced motion.</p>
     <p id="javascript" style="display: none">JavaScript is enabled.</p>
     <iframe src="/etc/passwd"></iframe>
     <iframe src="\\localhost/etc/passwd"></iframe>

test/integration/testdata/header-footer-html/header.html

@@ -8,6 +8,7 @@
     </style>
   </head>
   <body>
+    <span class="date"></span>
     <span class="title"></span>
   </body>
 </html>