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Create production extension artifacts for one or more browser targets. build compiles your extension in production mode and writes output to dist/<browser>. For monorepo/submodule projects, see Environment variables for config-time env resolution (project root first, then workspace-root fallback).

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When to use build

  • Preparing extension packages for Chrome Web Store, Edge Add-ons, or Firefox Add-ons.
  • Running continuous integration (CI) jobs that produce deterministic release artifacts.
  • Validating production bundle output and browser-target differences before submission.

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Build command capabilities

CapabilityWhat it gives you
Production compilationGenerate optimized extension artifacts per target
Multi-target outputBuild multiple browser targets in one command
Packaging supportCreate distribution zip artifacts with optional source bundle
CI-friendly behaviorKeep build outputs and naming predictable in automation

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Usage

extension build [project-path] [options]

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Build output

After running build, Extension.js generates optimized files for the selected browser targets. Output goes to dist/ with one subfolder per target. Each folder contains bundled JavaScript, CSS, HTML, and required runtime assets. Example output structure: 
dist/
├── chrome/
│   ├── manifest.json
│   ├── background/service_worker.js
│   ├── content_scripts/content-0.js
├── edge/
│   ├── manifest.json
│   ├── background/service_worker.js
│   ├── content_scripts/content-0.js

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Browser target matrix

Target styleExamplesNotes
Named targetschromium, chrome, edge, firefoxBuild one specific browser target
Engine targetschromium-based, gecko-based, firefox-basedUseful for engine-family workflows
Multi-targetchrome,firefoxComma-separated targets

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Arguments and flags

FlagAliasWhat it doesDefault
[path]-Builds a local extension project.process.cwd()
--browser <browser>-Browser or engine target (chromium, chrome, edge, firefox, engine aliases, or comma-separated values).chromium
--polyfill [boolean]-Enables browser.* API compatibility polyfill for Chromium targets.false
--zip [boolean]-Creates a packaged zip artifact.false
--zip-source [boolean]-Includes source files in zip output.false
--zip-filename <name>-Sets custom zip filename.extension name + version
--silent [boolean]-Suppresses build logs.false
--extensions <list>-Comma-separated companion extensions or store URLs.unset
--install [boolean]-Install project dependencies when missing.command behavior default
--author--author-modeEnable maintainer diagnostics.disabled

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Shared global options

Also supports global flags.

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Zip behavior

OptionEffectTypical use
--zipCreates a packaged artifact zipStore submission/manual distribution
--zip-filenameSets custom zip nameCI naming conventions
--zip-sourceAdds source archive alongside artifactsCompliance/review pipelines

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Examples

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Building with zip output and custom filename

extension build ./my-extension --browser=edge,chrome --zip --zip-filename=my-extension.zip
In this example, the build targets Edge and Chrome, zips the output, and saves it as my-extension.zip.

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Building with polyfill support

extension build ./my-extension --browser=chrome,firefox --polyfill
In this example, the build targets Chrome and Firefox and includes polyfill support where relevant.

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Building source and artifact zip

extension build ./my-extension --zip --zip-source

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Best practices

  • Check build logs: Review logs for warnings and missing assets after each build.
  • Optimize your manifest: Keep manifest.json compatible with every target browser.
  • Name artifacts intentionally: Use --zip-filename for stable CI artifact naming.
  • Validate target output: Check each dist/<browser> folder before publishing.

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Next steps