How to Use Redis as Cache: Simple Guide with Examples

To use Redis as a cache, store data with SET commands and retrieve it with GET. Use expiration times with EXPIRE or SETEX to automatically remove stale data and keep cache fresh.

Syntax

Redis caching mainly uses these commands:

• SET key value [EX seconds]: Store a value with an optional expiration time in seconds.
• GET key: Retrieve the value stored at the key.
• DEL key: Remove a key and its value from cache.
• EXPIRE key seconds: Set or update expiration time for a key.

These commands let you save data temporarily and fetch it quickly.

redis

SET user:123 "John Doe" EX 300
GET user:123
DEL user:123
EXPIRE user:123 600

Example

This example shows how to cache a user's name for 5 minutes and then retrieve it.

redis

127.0.0.1:6379> SET user:1001 "Alice" EX 300
OK
127.0.0.1:6379> GET user:1001
"Alice"
127.0.0.1:6379> TTL user:1001
299

Output

"Alice"

Common Pitfalls

Common mistakes when using Redis as cache include:

• Not setting expiration time, causing stale data to stay forever.
• Using keys without a clear naming pattern, making management hard.
• Ignoring cache misses and not falling back to the original data source.

Always set expiration and handle missing keys gracefully.

redis

;; Wrong: No expiration set
SET session:abc123 "data"

;; Right: Set expiration to 10 minutes
SET session:abc123 "data" EX 600

Quick Reference

Remember these tips for effective Redis caching:

• Use SET key value EX seconds to store data with expiration.
• Use consistent key naming like type:id (e.g., user:1001).
• Check for GET returning null and reload data if needed.
• Use DEL to clear cache when data changes.

Key Takeaways

Always set expiration on cached data to avoid stale entries.

Use clear, consistent key names for easy cache management.

Handle cache misses by fetching fresh data from the main source.

Use Redis commands SET, GET, EXPIRE, and DEL for caching operations.