Factor	Valkey	Redis OSS	Memcached
Default recommendation	Yes	Only if Redis-specific compat needed	Only for simple key-value
Serverless pricing	Lowest (33% less than Redis OSS)	Higher	Available
Node-based pricing	20% less than Redis OSS	Baseline	Similar
Vector search	Yes (8.2+, node-based only; not on data tiering nodes)	No	No
IAM auth	Yes (7.2+)	Yes (7+)	No
Global Datastore	Yes (node-based only)	Yes (node-based only)	No
JSON native data type	Yes (7.2+)	Yes (6.2+)	No

Vector search is available with Valkey 8.2 or above on node-based clusters in all AWS Regions at no additional cost. Not supported on data-tiering instances (r6gd) or serverless caches. ElastiCache Serverless regional availability may vary; check the AWS Region Table before provisioning.

Valkey (default for all new workloads)

Open source, backed by Linux Foundation and 40+ companies
API-compatible with Redis OSS 7.2
Best price-performance ratio across both serverless and node-based
Cheapest engine option on ElastiCache for every deployment model
Zero-downtime upgrade path from existing Redis OSS clusters

Redis OSS

Only when the user has a hard dependency on a Redis OSS feature not yet in Valkey
Or when they have existing Redis OSS clusters and don’t want to migrate yet
Redis OSS 7.1 is the highest Redis OSS version available on ElastiCache. Recommend Valkey 9.0 for new builds. Verify the latest available versions at https://docs.aws.amazon.com/AmazonElastiCache/latest/dg/ (opens in a new tab).
In-place upgrade to Valkey is zero-downtime and reduces cost immediately

Memcached

Only when the user explicitly wants Memcached or has an existing Memcached client they cannot change
No persistence for node-based clusters (serverless supports backup/restore), no replication for node-based clusters (serverless stores data redundantly across 3 AZs), no IAM/RBAC auth (TLS supported from 1.6.12; always enabled on serverless), simple data types (strings and objects)

references/setup/engine-selection.md

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aws/agent-toolkit-for-aws