AWS Lambda is a service which computes the code without any server. The code is executed based on the response of events in AWS services such as adding/removing files in S3 bucket, updating Amazon DynamoDB tables, HTTP request from Amazon API Gateway etc.
AWS Lambda is a AWS Service allowing you to run code :
- without managing servers
- paying only the compute time (code is running)
- it scales when need automatically
- it offers availability and fault tolerance