Interesting read on how Event Prioritization and Introducing a Data Stream to manage data asynchronously helped the team to increase the performance of the system and handle corner cases.

1. They prioritized events to make sure important events do not suffer
2. Introduced a layer (stream) instead of writing directly to the database
3. Reduce Conumse priority if the time taken is beyond a limit
4. Rate Limiting to filter out probable DOS events

https://engineering.razorpay.com/how-razorpays-notification-service-handles-increasing-load-f787623a490f