Amazon DynamoDB On-Demand – No Capacity Planning and Pay-Per-Request Pricing

January 31, 2025: Post updated to clarify the reduced on-demand pricing and workloads recommendations.

Just a few years ago, creating a database that could support your business at any scale while providing consistent low latency was a daunting task. That changed for me in 2012 while reading Werner Vogels’ blog post announcing Amazon DynamoDB (it was a few months before I joined AWS). DynamoDB was built on the principles in the original Dynamo paper that Amazon published in 2007. Over the years, lots of new features have been introduced to further simplify how AWS customers use databases. You can now create fully managed, multi-region, multi-master database tables with features such as encryption at rest, point-in-time recovery, in-memory caching, and a 99.99% uptime service level agreement (SLA).

Amazon DynamoDB on-demand
Today we are introducing Amazon DynamoDB on-demand, a flexible new billing option for DynamoDB capable of serving thousands of requests per second without capacity planning. DynamoDB on-demand offers simple pay-per-request pricing for read and write requests so that you only pay for what you use, making it easy to balance costs and performance. The Amazon DynamoDB on-demand capacity mode offers a truly serverless database experience that automatically scales to accommodate the most demanding workloads without capacity planning. On-demand simplifies the setup process, eliminates capacity management and monitoring, and provides fast, automatic scaling. With pay-per-request pricing, you don’t have to worry about idle capacity because you only pay for the throughput you actually use. You are billed per read or write request, so your costs directly reflect your actual usage.

In the DynamoDB console, you can choose the on-demand read/write capacity mode when creating a new table, or change it later in the Capacity tab.

Tables using on-demand mode support all DynamoDB features (such as encryption at rest, point-in-time recovery, global tables, and so on) with the exception of auto scaling, which is not applicable with this mode.

Indexes created on a table using on-demand mode inherit the same scalability and billing model. You don’t need to specify throughput capacity settings for indexes, and you pay by their use. If you don’t have read/write traffic to a table using on-demand mode and its indexes, you only pay for the data storage.

DynamoDB on-demand mode is the default and recommended throughput option for most DynamoDB workloads. DynamoDB handles all aspects of throughput management and scaling to support workloads that can start small and scale to millions of requests per second.

The following scenarios are a good fit for on-demand capacity mode:

• Developers working on serverless stacks with pay-per-use pricing
• SaaS provider and independent software vendors (ISVs) who want the simplicity and resource isolation of deploying a table per subscriber
• New tables with unknown workloads
• Applications with unpredictable traffic
• Bursty, new, or unpredictable workloads whose traffic can spike in seconds or minutes, and when under-provisioned capacity would impact the user experience

You can change a table from provisioned capacity to on-demand once per day. You can go from on-demand capacity to provisioned as often as you want.

A quick performance test
Let’s test some load on a newly created DynamoDB table using on-demand mode!

I created two serverless applications:

• The first application creates a REST API on top of a DynamoDB table using an AWS Lambda function and Amazon API Gateway. Using this API, you can read, add, update, and delete items in the table using HTTP methods such as get, post, put, delete.
• The second application starts 1,000 Lambda functions in parallel to generate load on the API endpoint, using random HTTP methods and random data for the items.

Each load generating function runs 100 concurrent requests, and when they are all terminated starts another 100, and so on, for one minute. There is no ramp-up period. Load generation starts immediately at full speed!

As you can see in the metrics tab for this table in the DynamoDB console, I reached a peak of almost 5,000 requests per second very quickly and without any throttling.

The scaling of the serverless stack, from API Gateway to the Lambda function and the DynamoDB table, was fully managed. I didn’t have to plan for the right throughput, and I could focus on the application logic I was building.

With DynamoDB on-demand you pay only for what you use. You can consult the DynamoDB on-demand pricing page for more details.

You can use the AWS Command Line Interface (AWS CLI), AWS SDKs, and AWS CloudFormation to create a table using on-demand mode or to change the read/write capacity mode of an existing table.

Available now
The DynamoDB on-demand is available globally in all commercial regions.

You can learn more on the read/write capacity modes in the DynamoDB developer guide.

I am really excited by the new possibilities for developers, ISVs and SaaS providers, and I look forward to seeing what you build with pay-per-request billing.