xUnit.net

Name: xUnit.net
Author: .NET Foundation

The modern .NET testing framework, and the one Microsoft's templates default to.

Unit & ComponentOpen sourceSelf-hostable

What it is

xUnit.net rethought NUnit's design for .NET: a new instance per test for isolation, constructor and IDisposable instead of setup/teardown attributes, and theories for data-driven tests. It integrates with dotnet test, Visual Studio and every .NET CI runner.

Best for

New .NET projects.

Where it is strong

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.

Where it falls short

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.

Pricing

Free and open source

Open source

Free tier: Everything, self-hosted

What drives the bill: Free and open source. You pay in engineering time and CI minutes.

Check current pricing on .NET Foundation’s site

Figures are indicative and were last reviewed August 2026. Vendors change pricing often; confirm before you commit.

Works with

dotnet testVisual StudioAzure DevOpsMoqGitHub Actions

What people who use xUnit.net say

No reviews of xUnit.net yet. If you have used it in anger, yours would be the first.

Alternatives to xUnit.net

If xUnit.net is not the right fit, these solve the same problem differently.

NUnit

Unit & Component

The long-standing .NET test framework with the richest assertion set.

Open sourceSelf-host

xUnit.net vs NUnit