Hi @Mikkel_Damm,
Welcome to MongoDB community!
How do you set your MongoDB drivers on Lambda? Does each lambda has its own connection pool?
Do you limit those connection pools and how?
In general since AWS lambda is like any other server from Atlas perspective it needs to enforce the connection limit on lambda side.
For this reason we encourage customers to explore realm functions and webhooks as realm optimized to not exceed cluster connection with smart internal connection pooling.
Best
Pavel