Install web-ext with Homebrew, MacPorts, Nix

Project links

• Homepage
• Upstream docs
• Package manager page

Commands and aliases

• web-ext

Project history

Mozilla created the public web-ext repository and npm package in February 2016, while WebExtensions support was still stabilizing in Firefox. Mozilla's April 2016 add-ons blog described WebExtensions in Firefox 48 and pointed to web-ext as the command-line tool that would automate reloads during add-on development.

The 1.0.0 npm release landed in April 2016. By July 2016, Mozilla was already describing web-ext 1.0 as announced and following up with automatic extension reloading and source linting, two features that became central to the tool's everyday value.

The tool continued as part of Firefox Extension Workshop documentation rather than as an abandoned migration helper. By 2026, npm showed a long release history through the 10.x series, while the official command reference documented the current major-version command set.

Adoption history

web-ext became the standard Mozilla-supported CLI for WebExtension developers because it matches the repetitive tasks of extension work: run the extension in a temporary Firefox profile, watch files, reload after edits, package the source as a zip, and sign or submit builds for addons.mozilla.org.

The broader adoption story is tied to Firefox's move away from legacy extension systems toward the cross-browser WebExtensions model. Even when an extension targets multiple browsers, web-ext remains useful for Firefox-specific testing, AMO signing, Android extension testing, and making Firefox profile state disposable during development.

How it is used

The common development loop is to change into an extension source directory and run `web-ext run`, which starts Firefox with the extension temporarily loaded and reloads it after source changes. When the extension is ready, `web-ext build` creates a package and `web-ext sign` can use addons.mozilla.org API credentials to produce or submit signed artifacts.

The tool also supports configuration files and package.json configuration, so teams can put source directories, ignore patterns, signing settings, and other options under version control or local developer configuration. This makes it a small but important bridge between browser-extension code and ordinary command-line build automation.

Why package nerds care

web-ext matters in package-manager culture because it turns a browser UI workflow into a scriptable developer tool. Installing it with npm, Homebrew, MacPorts, or Nix lets extension developers use the same shell habits they use for compilers, linters, and bundlers, while still targeting Firefox's extension runtime and AMO publishing requirements.

Timeline

• 2016-02: Mozilla created the public web-ext repository and first npm package.
• 2016-04: web-ext 1.0.0 was published as Firefox 48-era WebExtensions support stabilized.
• 2016-07: Mozilla documented follow-up work adding automatic reload and linting to the young tool.
• 2024: The npm release stream reached web-ext 8.x, matching a separately documented v8 command reference.
• 2026: npm listed web-ext 10.4.0 as the current package version.

Related projects

• web-ext sits beside Mozilla's addons-linter, addons.mozilla.org signing APIs, MDN WebExtensions documentation, and browser-specific extension debugging pages such as about:debugging. It is also adjacent to cross-browser extension frameworks that eventually call into browser-specific build or signing steps.

Sources

• https://api.github.com/repos/mozilla/web-ext
• https://blog.mozilla.org/addons/2016/04/29/webextensions-in-firefox-48/
• https://blog.mozilla.org/addons/2016/07/27/linting-and-automatically-reloading-webextensions/
• https://extensionworkshop.com/documentation/develop/getting-started-with-web-ext/
• https://github.com/mozilla/web-ext
• https://www.npmjs.com/package/web-ext