JUnit 5 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.

JUnit 5xUnit.net

Entry price

Free and open source

Open source

Free and open source

Open source

What drives the bill

The metric that actually scales your invoice.

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

Free tier

Everything, self-hosted

Open source

EPL-2.0

Apache-2.0

Self-hostable

No-code authoring

Languages

JavaKotlin

Platforms

WebAPI

WebAPIDesktop

Fits teams

Solo / side projectStartupScale-up / mid-marketEnterprise

StartupScale-up / mid-marketEnterprise

Adoption

Category standard

JUnit Team · since 2017

Category standard

.NET Foundation · since 2007

Strengths

Universal support across IDEs, build tools and CI in the Java ecosystem.
The extension model replaced JUnit 4's runners and rules with something composable.
Pairs cleanly with Mockito, AssertJ, Spring Test and Testcontainers.

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

Java verbosity persists — expect more lines per test than in Python or JavaScript.
Parallel execution is opt-in and still occasionally surprising.
Mixed JUnit 4 and 5 codebases need the vintage engine and stay confusing for years.

Best for

Every Java and Kotlin project on the JVM.

New .NET projects.

Pricing last reviewed August 2026 and is indicative only — confirm on each vendor’s own page.