NUnit vs Vitest

Free and open source

Free and open source

Free and open source. You pay in engineering time and CI minutes.

Free and open source. You pay in engineering time and CI minutes.

Everything, self-hosted

Everything, self-hosted

Widely used

.NET Foundation · since 2002

Category standard

VoidZero / OSS community · since 2021

• The most expressive built-in assertion library in .NET.
• Familiar attribute model for teams migrating from older frameworks.
• Very stable, very long-lived.

• Fastest watch-mode feedback of the JavaScript runners, by a wide margin on large repos.
• Zero-config ESM and TypeScript — the single biggest source of Jest configuration pain simply disappears.
• Jest-compatible API means migration is usually a day, not a quarter.

• Shared test-class instances mean state can leak between tests unless you are careful.
• New Microsoft templates default to xUnit, so it is drifting from the mainstream.
• Attribute-heavy style feels dated.

• Assumes Vite. On a Webpack or Metro project the advantage largely evaporates.
• Younger ecosystem; a handful of niche Jest plugins have no equivalent.
• Browser mode is still maturing relative to a dedicated component test runner.

Existing .NET codebases already standardised on NUnit.

Any Vite-based project, and most new JavaScript projects generally.