Caches
A cache is a Valkey server of its own: Redis-compatible, BSD-licensed, for caching, queues (Celery, BullMQ, Sidekiq, arq) and sessions. Any Redis client works with it.
Create and link
New → Cache on the project's page. Link it to an app in the app's Settings → Resources: on its next deploy the app gets
| Variable | Value |
|---|---|
REDIS_URL |
redis://default:<password>@cache-12:6379/0 |
VALKEY_URL |
the same |
REDIS_HOST |
cache-12 |
REDIS_PORT |
6379 |
REDIS_PASSWORD |
the generated password |
Each cache runs in its own container on its project's network: only that project's apps reach it, and only with its password.
Memory
A cache starts with 256 MB; change it on its page, and it restarts with its data. When it's full, writes fail and nothing is evicted, so a queue never silently loses jobs. For a plain cache, give keys a TTL.
Its data
What's in a cache outlives restarts and redeploys (an append-only file in a volume), but it isn't backed up. Keep nothing there you can't rebuild; put it in a database.
Replace all secrets gives every cache a new password; it restarts with its data, and its apps get the password on their restart.