Can DynamoDB be used as a cache?

Yes. DynamoDB's fast key-value lookups and TTL make it a solid durable cache — for sessions, tokens, and computed results. For sub-millisecond reads, pair it with DynamoDB Accelerator (DAX), a fully managed in-memory, write-through cache that fronts the table and returns eventually consistent reads in microseconds without any cache-invalidation code.

DynamoDB as a durable cache

Because reads are keyed and single-digit-millisecond, DynamoDB works well as a persistent cache layer. TTL automatically expires stale entries at no cost, so cached sessions or precomputed results clean themselves up.

Adding DAX for microseconds

DAX is an in-memory cache that sits in front of DynamoDB:

• Read-through / write-through — it manages population and invalidation for you.
• Microsecond reads — up to a 10x improvement on eventually consistent reads.
• API-compatible — minimal application changes.

When it fits and when it does not

Great for read-heavy workloads that tolerate eventual consistency (DAX serves eventually consistent data). If you need strong consistency on every read, go to the table directly.

Go deeper

Read DynamoDB TTL and DynamoDB consistency. Download DynoTable to inspect your cache tables.