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A simple tool that allows you to execute JavaScript code in multiple real browsers.

The main purpose of Karma is to make your test-driven development easy, fast, and fun.

Karma is deprecated and is not accepting new features or general bug fixes.

The web testing space has evolved significantly in the 10+ years since Karma's creation. The web landscape looks very different today and new patterns and tools have emerged in the ecosystem. New test runners offer more performant alternatives, and Karma no longer provides clear unique value.

Based on the current state of the web testing ecosystem, we have made the hard decision to deprecate Karma.

We know Karma is used particularly commonly in the Angular ecosystem, so Angular is adding Jest and Web Test Runner support to provide a migration path off of Karma. See the Angular blog for more details.

Critical security issues in Karma will still be triaged and fixed as necessary. This will continue until 12 months after Angular CLI's Web Test Runner support is marked stable.

For those outside Angular looking to migrate off Karma, both Web Test Runner and jasmine-browser-runner provide browser-based unit testing solutions which can be used as a direct alternative. Jest and Vitest also provide Node-based alternatives.

It has been incredible to see Karma's impact on the web testing ecosystem and we greatly appreciate the support of everyone who contributed to an awesome community. Keep testing. ✅

Help and Support

For questions and support please use the mailing list or Gitter. The issue tracker is for bug reports and feature discussions only.

When should I use Karma?

  • You want to test code in real browsers.
  • You want to test code in multiple browsers (desktop, mobile, tablets, etc.).
  • You want to execute your tests locally during development.
  • You want to execute your tests on a continuous integration server.
  • You want to execute your tests on every save.
  • You love your terminal.
  • You don't want your (testing) life to suck.
  • You want to use Istanbul to automagically generate coverage reports.
  • You want to use RequireJS for your source files.

But I still want to use _insert testing library_

Karma is not a testing framework, nor an assertion library. Karma just launches an HTTP server, and generates the test runner HTML file you probably already know from your favourite testing framework. So for testing purposes you can use pretty much anything you like. There are already plugins for most of the common testing frameworks:

If you can't find an adapter for your favourite framework, don't worry and write your own. It's not that hard and we are here to help.

Which Browsers can I use?

All the major browsers are supported, if you want to know more see the browsers page.


See FAQ.

I want to use it. Where do I sign?

You don't need to sign anything but here are some resources to help you to get started...

Obligatory Screencast.

Every serious project has a screencast, so here is ours. Just click here and let the show begin.


See installation.

Using it.

See configuration.

This is so great. I want to help.

Please, see contributing.

Why did you create this?

Throughout the development of AngularJS, we've been using JSTD for testing. I really think that JSTD is a great idea. Unfortunately, we had many problems with JSTD, so we decided to write our own test runner based on the same idea. We wanted a simple tool just for executing JavaScript tests that is both stable and fast. That's why we use the awesome Socket.io library and Node.js.

My boss wants a license. So where is it?

MIT License

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