Flawless traps exceptions and then uses git blame to send an email to the developer who wrote the buggy code. Even if a particular line of code causes thousands of exceptions, only one email will be sent. It uses git-blame to figure out which developer is responsible for a particular exception, and will only email that developer. If you set report_only_after_minimum_date, then Flawless will only report exceptions caused by code modified after report_only_after_minimum_date. You can mark certain files/functions as library code, and when an exception originates in those files/functions, the caller will be blamed for the error instead of the library code.