Amazon DynamoDB Accelerator (DAX)
In-memory cache for DynamoDB
DAX: an in-memory cache cluster in front of DynamoDB, compatible with the DynamoDB API, cutting read times from milliseconds to microseconds with almost no code changes.
- Cost$$ Medium
- Difficulty●●●●●
- Costs money when idle?Yes
- Managed by AWS
- In examsSAA · DVA
Think of it asLike a bestseller shelf right at the checkout counter, so you don't have to run to the stockroom.
When to use it
✓ Use it when
Applications that read DynamoDB heavily and need microsecond latency or fewer RCUs for hot keys.
✗ Avoid it when
Write-heavy or need strongly consistent reads; caching for sources other than DynamoDB → ElastiCache.
Common uses
- Constantly read game leaderboards
- Product pages during sales
- Reducing DynamoDB read costs
What does it cost?
- Pricing model: Charged hourly for each node in the DAX cluster, by node type.
⚠️ Cost traps
Production clusters should have multiple nodes across multiple AZs, multiplying cost by the number of nodes.
Related services
SAA-C03 study guide
DAX is covered in these study modules: