# "Choosing a Cache on Zerops"


## Keywords
cache, redis, valkey, keydb, in-memory, session, key-value, choose cache, which cache

## TL;DR
**Use Valkey.** KeyDB development has stalled and is effectively deprecated on Zerops.

## Decision Matrix

| Need | Choice | Why |
|------|--------|-----|
| **Any caching need** | **Valkey** (default) | Active development, full HA, Redis-compatible |
| Legacy KeyDB apps | KeyDB | Only if migrating existing KeyDB deployment |

## Valkey (Default Choice)

- Redis-compatible drop-in replacement
- HA: 3 nodes (1 master + 2 replicas) with automatic failover
- Ports: 6379 (non-TLS), 6380 (TLS), 7000 (read replica non-TLS), 7001 (read replica TLS)
- Connection: `redis://:@:6379`
- HA detail: Ports 6379/6380 on replicas forward traffic to current master (Zerops-specific, not native Valkey)

## KeyDB (Deprecated)

- Development activity has slowed significantly
- Port: 6379
- **Do not use for new projects**

## Gotchas
1. **HA replication is async**: Brief data loss possible during master failover
2. **Port forwarding is Zerops-specific**: Replicas forward 6379/6380 to master — this is not standard Redis/Valkey behavior
3. **Read replicas use different ports**: 7000/7001 for direct replica reads

## See Also
- zerops://themes/services — Valkey, KeyDB service cards and wiring
- zerops://decisions/choose-database