For MongoDB specifically see the best practices docs for Lambda (https://www.mongodb.com/docs/atlas/manage-connections-aws-lambda/ https://www.mongodb.com/docs/

For MongoDB specifically see the best practices docs for Lambda (https://www.mongodb.com/docs/atlas/manage-connections-aws-lambda/ https://www.mongodb.com/docs/atlas/manage-connections-aws-la...). This outlines creating the handler outside the function context to allow the client to be reused between invocations.