DynamoDB with Lambda is, for me, the combination where serverless first becomes truly useful. In part 2 your API did answer, but it forgot what it had just said. Every request started from zero. Orders, comments, settings and forms, however, need a place to stay.

Today, therefore, your project gets a memory: a small guestbook. Anyone can write an entry through the HTTP API, and the newest entries come back page by page. Along the way you learn how to shape the table, use the AWS SDK v3 and grant only the permissions the function needs.

In short

DynamoDB is a serverless database you create in the CDK with a few lines; a Lambda function uses it over HTTPS and IAM, without a connection pool. If you choose the key to match your queries, you read with a cheap query instead of an expensive scan.…