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Valkey compatibility

Connect to Momento Cache with standard Valkey and Redis clients over RESP. The shared gateway supports a specific set of commands. Unsupported commands are rejected with the RESP error -Command not allowed. Check this page to verify compatibility before migrating a workload.

This allowlist is separate from credential permissions. An allowlisted, modeled command that the credential cannot run returns -NOPERM this user has no permissions to run the '<command>' command. Parser-unknown commands can instead return the ordinary Valkey unknown-command response. See Database command permissions.

Momento Cache runs Valkey 9. The gateway's supported-command contract below, not the upstream version alone, determines compatibility.

Supported​

The service supports all common Valkey data types and operations:

  • Strings, including counters and range operations.
  • Hashes, including per-field TTLs.
  • Lists (non-blocking), sets, and sorted sets, including type-specific scans.
  • Bitmaps, geo reads, and HyperLogLog.
  • Non-blocking streams.
  • Key management such as DEL, EXPIRE, TTL, TYPE, UNLINK.

Not supported​

The following categorized list names common exclusions. It is not an exhaustive list of every unsupported upstream Valkey command.

  • Transactions: MULTI, EXEC, DISCARD, WATCH, UNWATCH.
  • Pub/Sub: SUBSCRIBE, PSUBSCRIBE, SSUBSCRIBE, PUBLISH, SPUBLISH, PUBSUB, UNSUBSCRIBE, PUNSUBSCRIBE, SUNSUBSCRIBE.
  • Blocking commands: BLMOVE, BLMPOP, BLPOP, BRPOP, BRPOPLPUSH, BZMPOP, BZPOPMAX, BZPOPMIN, WAIT, WAITAOF, XREAD, XREADGROUP.
  • Database switching: SELECT. One connection serves one Database.
  • Scripting: EVAL, EVALSHA, EVAL_RO, EVALSHA_RO, FCALL, FCALL_RO, FUNCTION, SCRIPT.
  • Other notable exclusions: SCAN, SORT, RENAME, RENAMENX, COPY, RANDOMKEY, CLIENT, SUNIONSTORE, SINTERSTORE, SDIFFSTORE, ZUNIONSTORE, ZINTERSTORE, and ZDIFFSTORE. Use HSCAN, SSCAN, or ZSCAN instead of top-level SCAN.

Custom modules​

Accounts with an Enterprise support plan can coordinate custom-module deployments with their account support representative. Recommended modules include JSON, Search, and Bloom. Search also provides vector search. Review required module commands with your representative when arranging deployment.

Protocol​

Connections start in RESP2. Switch to RESP3 per connection with HELLO 3. RESP3 works with some limitations. Attribute responses are not supported, and a few response types convert approximately.

Authentication​

Authenticate with AUTH <username> <password>, where the username is your Database name and the password is a Momento API token. The Database is bound to the connection by the username. The SELECT command is not supported. See Connectivity and the gateway.