Another way to track changes in a DynamoDB table is to enable streams. A stream is able to output all changes being made in the DynamoDB table to an interface where other services are listening for changes.

For example, when our users log in, we want to have a system that tracks the login time and performs some kind of advanced security check on top of each login event. As soon as the user logs in to the environment, a login entry will be created in the DynamoDB table. That record can be instantly output into the stream and a security service can listen on the backend to the stream and perform the necessary security check for each entry.

The streams can output information about each item that is being changed and we can configure the delivery of just the partition key, the old data in the table, the newly written data in the table, or both the new and the old data simultaneously. DynamoDB streams can also be utilized to trigger lambda functions, to provide real-time analytics, or output the changes of a DynamoDB table to another DynamoDB table or any other compatible AWS service.