Jest vs Vitest: Complete Comparison Guide
Compare Jest and Vitest on speed, configuration, ESM support, and developer experience. Discover which JavaScript test framework best fits your project.
Jest
The most popular JavaScript test framework, developed by Meta (Facebook). Jest provides an all-in-one solution with built-in assertion library, mocking, snapshot testing, code coverage, and parallel test execution. With over 45,000 GitHub stars and a massive ecosystem, Jest is the de facto standard for JavaScript and TypeScript testing.
Vitest
A blazing-fast unit test framework that works natively with Vite. Vitest provides a Jest-compatible API, ESM-first support, hot module replacement for tests, and out-of-the-box TypeScript/JSX support. The framework is 2 to 5 times faster than Jest thanks to Vite's transformation pipeline and intelligent file watching.
Comparison table
| Feature | Jest | Vitest |
|---|---|---|
| Speed | Fast with worker threads, but slower cold starts due to transformation | 2-5x faster thanks to Vite's native ESM and esbuild transformations |
| ESM support | Experimental ESM support, CommonJS-based by default | Native ESM-first — no configuration needed for ES modules |
| Configuration | Extensive configuration needed for TypeScript, ESM, path aliases | Reuses Vite configuration — minimal extra setup |
| Mocking | Built-in jest.mock() with automatic hoisting — very powerful | vi.mock() with comparable API, plus native module mocking |
| Ecosystem | Massive ecosystem: testing-library, dozens of plugins, broadly documented | Growing ecosystem, Jest-compatible API makes migration easy |
| Watch mode | File watcher with pattern matching for targeted tests | HMR-based watch — only changed tests are re-run |
Verdict
Vitest is the future of JavaScript testing and is rapidly gaining ground on Jest. Its superior speed, native ESM support, and Vite integration make it ideal for modern projects. Jest remains a solid choice for existing projects with extensive test suites and for teams that value the broader ecosystem and proven stability. Vitest's Jest-compatible API makes migration relatively straightforward, enabling a gradual transition.
Our recommendation
At MG Software, we use Vitest as our standard test framework for all new projects. The seamless integration with our Vite/Next.js stack, blazing-fast feedback loops, and native TypeScript support perfectly align with our workflow. For existing client projects still on Jest, we offer migration guidance to Vitest. The switch typically yields a 2-4x faster test suite, significantly improving the developer experience.
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