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Alex Spinov
Alex Spinov

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Redis Has a Free In-Memory Data Store — Cache, Queues, and Pub/Sub in One Tool

#redis #database #devops #backend

Redis stores data in memory for sub-millisecond reads. Use it as a cache, message queue, session store, rate limiter, and real-time leaderboard — all in one tool.

More Than a Cache

Most developers use Redis for caching. But Redis is a full data structure server with use cases far beyond cache.

What You Get for Free

Data structures:

  • Strings — cache values, counters, flags
  • Hashes — user profiles, object properties
  • Lists — queues, activity feeds, recent items
  • Sets — tags, unique visitors, intersections
  • Sorted Sets — leaderboards, priority queues, time-series
  • Streams — event sourcing, message queues (like Kafka-lite)
  • Pub/Sub — real-time messaging between services

Common patterns:

# Cache with TTL
SET user:123 '{"name":"Alice"}' EX 3600

# Rate limiting
INCR api:rate:user:123
EXPIRE api:rate:user:123 60

# Leaderboard
ZADD leaderboard 1500 "player1"
ZADD leaderboard 2000 "player2"
ZRANGE leaderboard 0 9 REV WITHSCORES

# Job queue
LPUSH jobs '{"type":"email","to":"alice@test.com"}'
BRPOP jobs 0  # blocking pop (worker waits)

# Pub/Sub
SUBSCRIBE notifications
PUBLISH notifications 'new-order'
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Quick Start 

# Docker (recommended)
docker run -d --name redis -p 6379:6379 redis:7-alpine

# Node.js
npm i ioredis
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import Redis from 'ioredis';
const redis = new Redis();

await redis.set('key', 'value', 'EX', 3600);
const value = await redis.get('key');
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Performance

  • 100,000+ operations/second on a single instance
  • Sub-millisecond latency for reads and writes
  • Persistence options: RDB snapshots, AOF log, or both
  • Clustering: shard data across multiple nodes
  • Replication: master-replica for high availability

Redis Stack (Free Add-ons)

  • RedisJSON — native JSON document storage
  • RediSearch — full-text search with secondary indexes
  • RedisTimeSeries — time-series data with aggregation
  • RedisBloom — probabilistic data structures

If your app makes the same database query twice — Redis between your app and database will make it 100x faster.

Need web scraping or data extraction? Check out my tools on Apify — get structured data from any website in minutes.

Custom solution? Email spinov001@gmail.com — quote in 2 hours.

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