Insomnia vs Rentgen is one of those comparisons that sounds logical until you actually think about it for more than five seconds. Yes, both deal with APIs, but so does electricity and your toaster, and nobody is comparing those. Insomnia is a proper API platform. You build requests, manage collections, write assertions, run tests, sync with Git, collaborate with teams and generally behave like a responsible adult. It’s structured, repeatable, and absolutely necessary once your API stops being a toy and starts becoming a system. Rentgen doesn’t even try to compete with that. It shows up earlier, at that suspiciously quiet moment when the first request returns 200 and everyone suddenly decides the job is done. That’s where things usually go wrong. Because one clean request doesn’t prove the API works, it proves that one carefully crafted scenario didn’t explode. Insomnia works with what you define. If you don’t test missing fields, they don’t exist.…