For iOS, we highly recommend only having one crash reporter turned on at a time. Using more than one may lead to a loss of crashes due to handler collisions and competition to receive data upon a user returning to the app.
If you decide to keep another tool like Firebase as your prominent crash reporter, Embrace will swizzle their message in an attempt to pull in the crashes Firebase is reporting into Embrace.In some cases, Embrace cannot pull the crash fast enough from Firebase before the app crashes. Please refer to our technical documentation for more information.
For Android, yes, Embrace adds itself as a listener for uncaught JVM exceptions, but we pass on exceptions to any handler that was registered when we registered ours so that both listeners will receive the uncaught exceptions.
For NDK exceptions, we replace any existing signal handlers, which are used to capture C and C++ exceptions. Similarly, other NDK crash capture tools would be likely to replace our signal handlers if they are initialized after our SDK.