Frida lets you hook behavior in apps. Think of it like mocking but for reverse engineers.

Would this help to reverse engineer an encrypted API?

Yes. For example you could hook the function that encrypts the outgoing payload and print it out before it is encrypted. And then for decryption you could hook the function that decrypts the payload as it comes in print out the result.

Going further, the API likely uses some secret key for encryption/decryption and you could hook that value out of the app as well.

Wow, that sounds really cool! Searching around i found this list: https://github.com/dweinstein/awesome-frida

Sadly the name "Frida" suffers from poor google-ability. But here you go: https://frida.re/

Basically it's _the_ reverse engineering toolkit for security researchers. Has excellent support across Android, iOS, macOS, Windows, etc.

I did not know that Frida is used for anything but Mobile apps, thanks :D

It helps you inject a js runtime in your apps which have access to everything via reflection.

No need to recompile the app after making changes to smali (decompiled but modifiable language).

As you can just modify the js script and get the modified behavior.