# Vitest vs Jest: which test runner should you choose?

> Start a new Vite app with Vitest. Keep an established Jest suite unless you have a concrete reason to move. What differs, and what to check first.

Web page: https://supercov.com/compare/vitest-vs-jest · Published 2026-09-13
All Supercov pages for agents: https://supercov.com/llms.txt · Full text: https://supercov.com/llms-full.txt

## Which should you choose?

For a new Vite application, start by trying Vitest: sharing the application's transform and configuration setup can reduce duplication. For an established Jest suite, keep Jest unless you have a concrete reason to move. Rewriting a working test setup is not automatically an improvement.

Both runners have assertions, mocks, snapshots, watch mode, and coverage. The more useful question is which one fits your application's build tools and test environment. [Vitest's comparison guide](https://vitest.dev/guide/comparisons) explains its relationship to Jest.

## Compare the workflow

| Decision | Vitest | Jest |
| --- | --- | --- |
| Vite application | Shares Vite's configuration and transforms | Configure Jest's transforms and aliases, or use an integration |
| Existing Jest tests | Similar APIs; migration still needs checks | Keep your existing configuration and integrations |
| TypeScript | Transforms TypeScript; type-check separately | Configure a transformer; type-check separately |
| Module mocking | `vi.mock` and Vitest's module rules | `jest.mock`; separate ESM mocking rules |
| Browser testing | Browser Mode runs tests in a real browser | jsdom simulates a DOM; it is not a real browser |
| Coverage providers | V8 or Istanbul | V8 or Babel/Istanbul |

This is a comparison of the usual built-in workflows, not a claim that plugins cannot extend either runner. Sources: [Vitest's Jest migration guide](https://vitest.dev/guide/migration/jest), [Jest's TypeScript setup](https://jestjs.io/docs/getting-started#using-typescript), [Jest's ESM guide](https://jestjs.io/docs/ecmascript-modules), and [Jest configuration](https://jestjs.io/docs/configuration).

## What changes when migrating from Jest?

A simple test is familiar in both:

```js
// Vitest
import { expect, test, vi } from 'vitest';

test('calls the callback', () => {
  const callback = vi.fn();
  callback('saved');
  expect(callback).toHaveBeenCalledWith('saved');
});
```

The equivalent Jest test imports from `@jest/globals` and uses `jest.fn()`. That small change is not a complete migration plan.

Before switching the whole suite, move one test from each important category: a module mock, an async test, a snapshot, and a component test. Check mock cleanup, setup files, globals, path aliases, and environment assumptions. Run both suites against the same application revision and investigate changed behavior rather than automatically updating snapshots.

## Do you need a real browser?

Use a DOM simulator for tests that do not depend on real layout or browser behavior. When focus, rendering, or browser APIs matter, use a real-browser workflow. Vitest's [Browser Mode](https://vitest.dev/guide/browser/) is one option; an end-to-end suite can remain a separate part of your project.

## Does switching runners give you deeper coverage?

Not by itself. Both runners' usual coverage reports tell you which code executed. A passing test can still check only that a result exists, rather than that its value is correct.

Supercov works with either runner when you want MC/DC, per-test coverage, and assertion review. It is **not a Vitest or Jest replacement**:

```sh
# Keep Vitest
npx supercov -- npx vitest run

# Or keep Jest
npx supercov -- npx jest
```

Choose the runner for your project. Then choose the coverage questions you need answered. For provider differences, read [V8 vs Istanbul coverage](https://supercov.com/compare/vitest-coverage.md); for missing checks, see [assertion coverage](https://supercov.com/docs/assertions.md). For Node.js code with no browser, also compare the [Node.js test runner with Jest](https://supercov.com/compare/node-test-vs-jest.md).