REST-assured and Rentgen: Different Tools, Different Jobs

People often compare REST-assured and Rentgen, but they solve different problems.

REST-assured is a Java library for building reliable API regression tests. You already know what the API should do, and you automate those expectations.

Rentgen starts earlier.

Give it one working cURL request and it explores how the API behaves with missing fields, invalid values, malformed payloads, authentication edge cases, unsupported methods, and more. The goal isn't to replace coded automation, but to discover what is actually worth automating.

A workflow that makes sense:

1. Build the endpoint.
2. Run it through Rentgen to understand its real behaviour.
3. Fix the obvious issues.
4. Capture the important scenarios with REST-assured.
5. Run everything in CI/CD.

Discovery first. Regression second.

Both tools belong in the same API testing workflow—they just solve different problems at different stages.

You can find the full story here: https://rentgen.io/api-stories/REST-assured-and-Rentgen-coded-API-tests-and-eality-check-before-them.html