One thing which was harder to do than expected was payments. During the development of the stripe payment logic, stripe significantly updated its flutter library for payments and introduced a new library for processing native payments. As this library was just created, it had some strange bugs, so some users experienced payment errors. These errors occurred only for 1% of users, so debugging it was pretty hard. So we’ve added firebase analytics to the app to log the crashes properly. We’ve found a few reasons for these payment crashes and decided to update the backend to use the stripe webhook. It helped us to guarantee that if users proceed with the payment =>, the API will properly handle it even though the user loses internet connection or closes the app.