Redis Best Practices

Standards for deploying and using Redis as a cache or key-value store.

1. Connection Management

• Connection Pooling: Use a persistent connection object across your application. Do not create a new Redis client on every request.
• Timeouts & Reconnects: Always configure connectTimeout and strict reconnect strategies. Redis can drop connections under load; your app must handle retries gracefully without stalling.

2. Caching Strategies

• Cache-Aside Pattern: Read from cache; if miss, read from DB and write to cache with a TTL.
• Thundering Herd: Use brief locks (distributed locking) or stale-while-revalidate patterns for heavily accessed keys that expire, to prevent database spikes.
• TTL (Time-To-Live): ALWAYS attach a TTL to cache keys unless the key is definitively a permanent config value. Use staggered TTLs (e.g., base TTL + random jitter) to avoid mass expirations.

3. Data Structures

• Hashes (HSET/HGET): Use Hashes to store objects instead of stringified JSON when you need to update or read individual fields.
• Sets (SADD/SMEMBERS): Use Sets for unique collections (e.g., user IDs online) and quick membership checks.
• Pipelines: Use MULTI/EXEC or Pipelines to batch commands together and save network round trips.

4. Security

• Never expose the Redis port (6379) to the public internet. Ensure it is accessible only within a VPC or private network.
• Use TLS (rediss://) and authentication for managed instances (e.g., AWS ElastiCache, Render Redis).