NUnit vs xUnit.net
Feature checklists rarely decide anything. What decides it is the pricing metric, who has to write the tests, and which limitation you can live with.
Entry price
Free and open source
Open sourceFree and open source
Open sourceWhat drives the bill
The metric that actually scales your invoice.
Free and open source. You pay in engineering time and CI minutes.
Free and open source. You pay in engineering time and CI minutes.
Free tier
Everything, self-hosted
Everything, self-hosted
Open source
MIT
Apache-2.0
Self-hostable
No-code authoring
Languages
Platforms
Fits teams
Adoption
Widely used
.NET Foundation · since 2002
Category standard
.NET Foundation · since 2007
Strengths
- The most expressive built-in assertion library in .NET.
- Familiar attribute model for teams migrating from older frameworks.
- Very stable, very long-lived.
- Per-test instance isolation eliminates a whole class of shared-state bugs by design.
- Idiomatic modern C# — no attribute soup.
- The default in current .NET project templates.
Limitations
- 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.
- Fewer built-in assertions than NUnit; most teams add FluentAssertions.
- The isolation model surprises developers migrating from NUnit.
- Parallelism defaults occasionally bite on integration tests.
Best for
Existing .NET codebases already standardised on NUnit.
New .NET projects.
All of these integrate with: dotnet test, Visual Studio, Azure DevOps, Moq.
Pricing last reviewed August 2026 and is indicative only — confirm on each vendor’s own page.