render-keyvalue

Render Key Value

Render Key Value provides low-latency, Redis-compatible in-memory storage running Valkey 8. Use it as a shared cache, session store, or job queue backend. Compatible with virtually all Redis client libraries.

When to Use

• Adding a cache or session store to a web app
• Wiring a job queue backend for Celery, Sidekiq, BullMQ, Asynq, or Oban
• Choosing the right maxmemory policy (cache vs queue)
• Configuring ipAllowList in Blueprints (required field)
• Connecting via internal vs external URLs
• Troubleshooting auth failures or connection refused errors

For background worker setup and queue framework patterns, see render-background-workers. For Blueprint authoring, see render-blueprints.

Key Concepts

Valkey 8 (not Redis)

New instances run Valkey 8, an open-source Redis fork. It is a drop-in replacement for Redis—existing Redis client libraries work without changes. Legacy instances (created before Feb 2025) run Redis 6.

Connection URLs

Every instance has two URLs:

URL type	When to use	Auth required
Internal (redis://red-xxx:6379)	From Render services in the same region	No (by default)
External (rediss://red-xxx:6379)	From outside Render (local dev, CI)	Always

Always prefer the internal URL for production services—lower latency, no TLS overhead, communicates over the private network.

External connections are disabled by default. Enable them by adding IP ranges to the access control list in the Dashboard.

Internal authentication

By default, internal connections are unauthenticated. You can require auth for internal connections in the Dashboard for compliance or extra security. This changes the internal URL to include credentials:

redis://default:PASSWORD@red-xxx:6379

Warning: Enabling internal auth breaks existing unauthenticated connections. Migrate clients to the authenticated URL first.

Maxmemory Policy

Critical decision. Choose based on your use case:

Use case	Policy	Why
Cache (can lose data)	allkeys-lru	Evicts least-recently-used keys to free space
Job queue (cannot lose data)	noeviction	Returns error on writes when full; never drops keys
Session store	allkeys-lru or volatile-lru	Sessions can be regenerated; LRU is safe

All available policies:

Policy	Behavior	Memory fills up?
allkeys-lru	Evict any key by LRU	No
noeviction	Error on writes when full	Yes
volatile-lru	Evict keys with TTL by LRU	Yes
volatile-lfu	Evict keys with TTL by LFU	Yes
allkeys-lfu	Evict any key by LFU	No
volatile-random	Evict random keys with TTL	Yes
allkeys-random	Evict any random key	No
volatile-ttl	Evict keys nearest to expiry	Yes

Blueprint Configuration

services:
  - type: keyvalue
    name: cache
    plan: starter
    region: oregon
    maxmemoryPolicy: allkeys-lru
    ipAllowList: []

ipAllowList is required

Blueprints must include ipAllowList on Key Value services. Common patterns:

Value	Meaning
[]	No external access (internal only—recommended for most apps)
[{source: "0.0.0.0/0", description: "everywhere"}]	Open external access (use sparingly)
[{source: "203.0.113.0/24", description: "office"}]	Specific IP ranges

Wiring to services

Use fromService with type: keyvalue and property: connectionString:

envVars:
  - key: REDIS_URL
    fromService:
      name: cache
      type: keyvalue
      property: connectionString

Available fromService properties for Key Value:

Property	Value
connectionString	Full internal URL (redis://red-xxx:6379)
host	Hostname only
port	Port only (typically 6379)

Data Persistence

• Paid instances: Disk-backed, appendfsync everysec. You may lose up to 1 second of writes on interruption.
• Free instances: No disk persistence. Data is lost on restart or upgrade.
• Upgrading from Free: All data is lost during the upgrade because Free instances have no disk.

Instance Types and Upgrades

• Instance type determines RAM and connection limit
• You can upgrade to a larger type (brief downtime, ~1-2 minutes)
• You cannot downgrade to a smaller type
• For instances larger than 10 GB RAM, contact Render support

Connection Examples

See references/connection-examples.md for client code in Node.js (ioredis, node-redis), Python (redis-py), Ruby (redis-rb, Sidekiq), and Go.

Common Mistakes

Mistake	Fix
Missing ipAllowList in Blueprint	Add ipAllowList: [] for internal-only access
Using allkeys-lru for job queues	Switch to noeviction—LRU eviction drops queued jobs
Connecting with external URL from a Render service	Use the internal URL for lower latency and no auth requirement
Forgetting type: keyvalue in fromService	type is required; without it the wiring fails
Using deprecated redis type alias	Prefer keyvalue in new Blueprints (redis still works but is deprecated)

References

Document	Contents
references/connection-examples.md	Client code for Node.js, Python, Ruby, Go
references/troubleshooting.md	Auth errors, connection refused, memory full, migration from Redis 6

Related Skills

• render-background-workers — Queue consumer setup with Celery, Sidekiq, BullMQ
• render-blueprints — Full render.yaml schema, fromService patterns
• render-networking — Private network, internal URLs
• render-env-vars — Wiring REDIS_URL and other connection vars