Amazon DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache for Amazon DynamoDB that delivers up to a 10 times performance improvement—from milliseconds to microseconds—even at millions of requests per second.
Though DynamoDB offers consistent single-digit-millisecond latency, DynamoDB + DAX takes performance to the next level with response times in microseconds for millions of requests per second for read-heavy workloads
With DynamoDB + DAX, you do not have to compromise on performance and scale. DAX lets you scale on demand. You can start with a three-node DAX cluster, and then add capacity by adding additional nodes. DAX lets you scale out to a 10-node cluster, giving you millions of requests per second.
DAX is tightly integrated with DynamoDB—you simply provision a DAX cluster, use the DAX client SDK to point your existing DynamoDB API calls at the DAX cluster, and let DAX handle the rest. Because DAX is API-compatible with DynamoDB, you don't have to make any functional application code changes.
DAX enables you to provision one DAX cluster for multiple DynamoDB tables, multiple DAX clusters for a single DynamoDB table, or somewhere in between to give you maximal flexibility.