I will develop AWS services like lambda, s3, dynamodb, sqs, sns, ses, rds

AWS Lambda is a serverless compute service that runs your code in response to events and automatically manages the underlying compute resources for you. It allows you to add custom logic to AWS resources such as Amazon S3 buckets, SQL(RDS) and Amazon DynamoDB tables, making it easy to transform data as it enters or moves through the cloud.

By using AWS Lambda service you pay only for the requests served and the compute time required to run your code. Billing is metered in increments of 100 milliseconds, making it cost-effective and easy to scale automatically from a few requests per day to thousands per second.

For example 1 : You want to create a DynamoDB/SLQ(RDS) tables and want set or get data from DynamoDB. The Lambda function will put and get record.

For example 2 : You want to create a serverless web site and do not want maintain server also want pay per usage. Here is solution S3, API Gateway, Lambda and RDS/DynamoDB.

For example 3 : You want to create a thumbnail or multiple sizes of images and want to compress these images when uploaded on s3 bucket. The Lambda function will resize and compress them on the fly.