Serverless Framework Function is a way of running code without provisioning or managing servers.
A Dead Letter Queue is a way of handling messages a consumer cannot process.
You can configure a Dead Letter Queue for your Serverless Function with the help of an SNS topic and the onError config parameter.
This parameter specifies the ARN of the SNS topic that will receive messages when your function fails.
One possible reason you should configure a Dead Letter Queue for your Serverless Function is to improve the reliability and resilience of your serverless application.
With a Dead Letter Queue, you can set aside and isolate messages that cause errors in your function and determine why their processing didn't succeed.
You can also retry or archive the messages for later analysis or processing.