REST Assured vs Karate

Free and open source

Free tier available

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

Open source core; Karate Labs sells a commercial IDE and enterprise support separately.

Everything, self-hosted

The open-source framework is complete and free.

Widely used

OSS community · since 2010

Widely used

Karate Labs · since 2017

• API tests live in the codebase, versioned and reviewed with the service.
• Readable given/when/then chains that map directly onto HTTP semantics.
• Full access to Java for setup, data and assertions.

• One DSL covers functional API tests, mocks and load tests — rare consolidation.
• Powerful JSON matching that removes most assertion boilerplate.
• Non-Java testers can write meaningful tests.

• Java only, and requires developers rather than manual testers.
• No GUI, so exploratory request work needs a separate client.
• Verbose for very large payload assertions.

• The custom DSL is another language to learn and cannot be refactored by an IDE.
• Debugging complex scenarios is harder than in plain code.
• The UI automation feature is far behind dedicated browser tools.

JVM teams that want API tests in the same repository as the service.

Teams wanting API testing and mocking in one tool, including non-Java testers.