Redis

Redis (Remote Dictionary Server) is an in-memory data structure store, used as a database, cache, and message broker. It is incredibly fast.

When to Use

• Caching: The #1 use case. Cache HTML, JSON, or DB results.
• Session Store: User sessions (speed + automatic expiry).
• Queues: Simple background job queues using Lists (LPUSH/RPOP).
• Real-time: Leaderboards, Counting, Pub/Sub.

Quick Start

# Set a value with 10 second expiry
SET session:123 "active" EX 10

# Increment a counter atomically
INCR page:views