DynamoDB Accelerator (DAX)

• Fully managed, highly available, in-memory cache for DynamoDB.

• Designed to reduce read congestion and deliver microsecond latency for reads.

• Ideal for read-heavy workloads.

Key Features

• Seamless integration with existing DynamoDB APIs — no changes to application logic required.

• Default Time to Live (TTL) for cache entries is 5 minutes (configurable).

• Caches individual items and query/scan results.

• Removes the need to manually manage cache invalidation.

Architecture

DAX vs. ElastiCache

• Purpose-built for DynamoDB.

• Caching is handled at the API level.

• Works transparently with DynamoDB SDK calls.

• Best for improving DynamoDB read performance without altering app code.

• General-purpose in-memory store (Redis / Memcached).

• Can cache results from any source (databases, APIs, computations).

• Requires application logic for cache reads/writes.

• More flexible, but not tied to DynamoDB.

Use DAX for direct DynamoDB acceleration.

Use ElastiCache for multi-source caching or custom caching strategies.