Shake feedback reporting
Issues that don't crash your app (those are called non-fatal issues) are not caught by Firebase Crashlytics at all.
On the other hand, Shake allows your team to finally get an insight into hundreds of those non-fatal issues your users experience daily:
they can't sign into your app
there's wrong data shown somewhere
they notice a visual glitch on one of your screens
there's a typo
a feature doesn't work the way they expected it to
Shake feedback reporting and Firebase Crashlytics complement each other.
Shake crash reporting
But we didn't stop. In 2021 we released a new product called Shake Crash, and just like Firebase Crashlytics, it tracks fatal issues. We believe it's better than Firebase Crashlytics because:
after your app crashes and the user returns to it → they are automatically asked to describe what happened in their own words (and vent so they don't leave you a bad review)
see which user precisely the crash happened to, it's not anonymous
automatically receive screen recording of the moments before their crash
automatically receive a beautiful timeline of user, network and console logs before the crash
Of course, Firebase Crashlytics is a more mature product and we invite you to use it too.
And to answer your last question: Yes, Shake Crash can be used in parallel with Firebase Crashlytics, they won't interfere with each other.