While developing your lambda functions, debugging may become a problem. As a person who benefits a lot from step-by-step debugging, I had difficulty debugging lambda functions. I got lost in the logs. Redeploying and trying again with different parameters over and over... then, I found the AWS Serverless Application Model (SAM) Command Line Interface (CLI). The AWS SAM CLI lets you debug your AWS Lambda functions in a good, old, step-by-step way.