restler-fuzzer VS cats

It is popular in domains where it’s effective but it’s not as useful when it’s hard to know if an output is correct. I know several tools which fuzz mobile app UIs to see if you can cause crashes or irrecoverable states with random inputs because those are easy to detect, but beyond that you start needing to have more traditional QA approaches to say whether the resulting state is correct.

One area which is very interesting is the use of OpenAPI schemas to help with APIs since you can use the schemas to guide generation and validation. It’s non-trivial to do with authentication but I found this project of interest:

https://github.com/microsoft/restler-fuzzer

There's another one here by Microsoft - this is cool though! great to see more Rust tools.

https://github.com/microsoft/restler-fuzzer

once you install git, just do git clone https://github.com/microsoft/restler-fuzzer

Out of this frustration I've built: https://github.com/Endava/cats. It's for APIs, but mostly addressing exactly this case: don't use strings for everything, if you choose to use it though, make sure you add patterns for checking if things are valid, make sure you think about all the corner cases and all the weird characters that can brake you app, and so on.

If the API has an OpenAPI spec available, you can use: https://github.com/Endava/cats

This is why we need better tools which will give benefits for the added complexity. If you need to create both the feature files AND the code, it's just complexity with little benefits. But frameworks like https://github.com/karatelabs/karate or https://github.com/Endava/cats are hiding this complexity and remove the code layer entirely. Which, in my view, this is where you need to be in 2023, particularly for API testing.

I've built a tool specifically to test if these kind of characters will reach API backends: https://github.com/Endava/cats. My idea was that APIs should explicitly reject or sanitise input containing such characters.

Cats by Endava