What are the best practices for using AWS DynamoDB with serverless architecture?

1 Choose the right partition key

The partition key is the attribute that determines how your data is distributed across DynamoDB partitions. It affects the throughput, latency, and scalability of your database. Therefore, you should choose a partition key that has high cardinality, meaning that it has many distinct values and avoids hot spots, meaning that it does not concentrate too much read or write activity on a single partition. For example, you can use a combination of attributes, such as user ID and timestamp, as your partition key, rather than a single attribute, such as status or category.

2 Use on-demand capacity mode

DynamoDB offers two capacity modes: provisioned and on-demand. Provisioned mode requires you to specify the amount of read and write capacity units (RCUs and WCUs) that you need for your table, and you pay for the provisioned capacity regardless of your actual usage. On-demand mode automatically adjusts the capacity based on your actual usage, and you pay only for what you use. On-demand mode is ideal for serverless architecture, as it eliminates the need to estimate or monitor your capacity, and it can handle unpredictable or bursty workloads without throttling or overprovisioning.

3 Leverage streams and triggers

DynamoDB streams capture the changes made to your table data in near real-time. You can use streams to process and react to these changes, such as replicating data to another table, updating a cache, or sending notifications. To do so, you can use AWS Lambda, a serverless compute service that lets you run code in response to events. Lambda can be configured as a trigger for DynamoDB streams, meaning that it will execute your code whenever a new stream record is available. This way, you can create serverless applications that are event-driven and decoupled.

4 Apply security and backup policies

DynamoDB provides several features to secure and protect your data, such as encryption at rest and in transit, fine-grained access control, and audit logging. You should use these features to enforce the principle of least privilege, meaning that you grant only the minimum permissions necessary for your users and applications to access your data. You should also enable point-in-time recovery (PITR) and continuous backups for your tables, which allow you to restore your data to any point in time within the last 35 days. Additionally, you should use AWS Backup, a serverless backup service that lets you create and manage backup policies across multiple AWS services, including DynamoDB.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?