Angular Testing in 2026: Jest, Karma, or Vitest?
for a new Angular project in 2026, use Vitest. It is the default test runner in the Angular CLI, and the Angular team calls its support stable and production ready. Karma is deprecated but still supported. Jest was only ever experimental in the CLI and is being phased out.
If you have been asking "which Angular testing tool should I choose in 2026?", this guide gives you a clear answer, a side-by-side comparison, and a safe migration path. It is written for Angular developers who want to pick once and not redo their test setup next year.
Why Angular Testing Changed
For years, "Angular testing" meant Jasmine + Karma. Jasmine gave you describe, it and expect. Karma launched a real browser and ran the tests inside it. It worked, but it was slow on large projects and Karma itself stopped getting new features.
The Angular team then tested several replacements: Jest, Web Test Runner and Vitest. After community feedback, they chose Vitest as the new default. Here is the timeline.
Karma is deprecated
Experimental Vitest support arrives
Vitest becomes the stable default
Experimental Jest and Web Test Runner support planned for removal in v22
Source: the official Angular v21 announcement.
Karma in 2026: Deprecated but Still Supported
What this means for you
Karma has been deprecated since 2023 and does not accept new features. However, the Angular team has said Karma and Jasmine are still fully supported, so existing apps do not have to migrate on day one.
Pros and cons
- Pro: tests run in a real browser, which is close to how users see your app.
- Pro: zero changes needed for existing suites.
- Con: slower feedback loop on large workspaces.
- Con: no future features, so the gap with modern tools will keep growing.
Verdict: keep Karma only for a legacy app you cannot touch right now. Plan an exit.
Jest in 2026: Popular, but Not Angular's Path
Where Jest fits
Jest is a very popular runner and assertion library with a huge ecosystem. Many Angular teams adopted it through community tooling such as jest-preset-angular because it runs in Node with jsdom and is fast to start.
The catch
The Angular CLI's own experimental Jest support was deprecated when Vitest became stable, with removal planned for v22. If you use Jest through a community preset, you are relying on that project and not on the CLI. That is a real maintenance risk for new work.
Verdict: if your team already runs Jest happily through a community setup, you can stay for now. For a new project, Vitest is the safer choice.
Vitest in 2026: The New Angular Default
Why Angular picked it
Vitest is built on the Vite ecosystem, has a Jest-style API (so the learning curve is small), and is now wired into the CLI. In a new Angular app you simply run ng test. Under the hood the CLI uses the @angular/build:unit-test builder.
Speed
Third-party write-ups report that Vitest can run large workspaces several times faster than Karma, with some claiming 5 to 10 times. Your result will depend on project size, hardware and test style, so measure your own suite before and after.
Simple Vitest example
import { TestBed } from '@angular/core/testing';
import { describe, it, expect } from 'vitest';
import { Counter } from './counter';
describe('Counter', () => {
it('increments the count', () => {
TestBed.configureTestingModule({ imports: [Counter] });
const fixture = TestBed.createComponent(Counter);
fixture.componentInstance.increment();
expect(fixture.componentInstance.count()).toBe(1);
});
});
Verdict: Vitest is the best choice for new Angular projects in 2026.
Jest vs Karma vs Vitest: Comparison
| Feature | Vitest | Jest | Karma |
|---|---|---|---|
| Angular CLI status | Default, stable | Experimental support being removed | Deprecated, still supported |
| Runs in | Node (jsdom/happy-dom) or browser mode | Node with jsdom | Real browser |
| Speed | Fast | Fast | Slower |
| Future updates | Actively developed with Angular | Community-driven for Angular | No new features |
| Best for | New projects and migrations | Teams already invested in Jest | Legacy apps |
Which one should you choose?
- Starting a new app? Choose Vitest.
- Maintaining a Karma app? Stay for now, then migrate gradually to Vitest.
- Already on Jest? Stay if it works well, but watch your preset's support and consider Vitest later.
How to Migrate from Karma to Vitest
Vitest support requires the modern application build system, which is the default in new projects. A common safe approach is progressive migration: keep Karma running, move test files over gradually, and remove Karma only when the Vitest suite is consistently green.
Step 1: Run the official schematic
ng generate @angular/core:karma-to-vitest
Step 2: Check your test builder
In angular.json, the test target should use the @angular/build:unit-test builder.
Step 3: Fix Jasmine-specific code
Replace Jasmine spies and matchers with their Vitest equivalents, for example spyOn becomes vi.spyOn. The schematic handles many common cases, but review the output.
Step 4: Run and measure
ng test
Compare run time and flaky tests with your old setup. Budget a few hours for a small app and more for a large one.
For a deeper walkthrough, read the Angular Architects migration guide and the official Angular testing documentation.
Conclusion
The Angular testing question in 2026 has a simple answer. Vitest is the future and the default, Karma is legacy but safe for now, and Jest is a valid community choice that is no longer Angular's direction.
If you are starting fresh, run ng new and write your first test with Vitest. If you have an older app, run the migration schematic on a branch and see how far it gets you. Either way, pick one runner and stick with it.
Want more on modern Angular? Read our guide Build a Scalable Angular App in 2026 (replace this link with the post URL) and explore more tutorials on AngularThink.
Frequently Asked Questions (FAQ)
Is Karma still supported in Angular 21?
Yes. Karma has been deprecated since 2023, but Karma and Jasmine remain fully supported by the Angular team, so you do not need to migrate immediately.
Is Vitest the default test runner in Angular?
Yes. Since Angular 21, new projects use Vitest by default when you run ng test.
Should I use Jest or Vitest for Angular in 2026?
For new projects, Vitest. It is built into the CLI and has a similar API to Jest. Stay with Jest only if your team already depends on a working community setup.
How do I migrate from Karma to Vitest?
Run ng generate @angular/core:karma-to-vitest, switch the test builder to @angular/build:unit-test, fix Jasmine-specific code and run ng test.
Is Vitest faster than Karma?
Usually yes, especially on large projects, because tests can run in Node without launching a full browser. Actual gains vary, so benchmark your own suite.
Can I run Karma and Vitest together?
Yes, during a gradual migration you can keep Karma while moving suites to Vitest, then remove Karma at the end.
