Comment by michal-stlv

Real lambda on AWS receives a request which is then forwarded to your local dev environment to handle it and return response which is then forwarded back to real lambda.

This way you can develop and test your code without constantly redeploying.

https://stelvio.dev/concepts/stelv-dev/

https://www.youtube.com/watch?v=W6aZFqBaH1g