Redis vs Memcached: Complete Comparison Guide
Compare Redis and Memcached on data structures, persistence, performance, and use cases. Discover which in-memory datastore best fits your caching strategy.
Redis
A versatile in-memory datastore that offers far more than caching. Redis supports diverse data structures including strings, hashes, lists, sets, and sorted sets. With built-in persistence (RDB and AOF), pub/sub messaging, Lua scripting, and Redis Streams, it serves as a complete data solution for real-time applications.
Memcached
A high-performance, distributed in-memory caching solution that excels in simplicity and high throughput. Memcached is multi-threaded and optimized for simple key-value caching with minimal overhead. It is battle-tested in large-scale production environments at companies like Facebook and Wikipedia.
Comparison table
| Feature | Redis | Memcached |
|---|---|---|
| Data structures | Strings, hashes, lists, sets, sorted sets, streams, bitmaps | Strings only (key-value) — simple and purpose-built |
| Persistence | RDB snapshots and AOF logging for durable storage | No persistence — data is lost on restart |
| Threading model | Single-threaded event loop (I/O threads from Redis 6) | Multi-threaded — efficient use of multiple CPU cores |
| Pub/Sub | Built-in pub/sub and Redis Streams for event-driven architectures | No messaging functionality |
| Memory efficiency | More overhead per key due to data structure metadata | Highly memory-efficient for simple key-value pairs |
Verdict
Redis and Memcached are both proven in-memory datastores but serve different needs. Redis is the more versatile choice thanks to its rich data structures, persistence, and pub/sub functionality. It functions as more than a cache — it is a complete data platform. Memcached, on the other hand, is optimized for one task: simple key-value caching with maximum throughput and minimal latency. Choose Redis when you need more than basic caching, and Memcached when pure caching performance is your primary requirement.
Our recommendation
At MG Software, we default to Redis as our caching and session solution due to its versatility and persistence capabilities. Redis fits excellently in our stack as a session store, rate limiter, and real-time pub/sub layer alongside Supabase. We also use Redis for background tasks via queue structures. We only recommend Memcached in specific scenarios where extremely high throughput for simple key-value caching is the sole requirement and the multi-threaded architecture provides an advantage.
Frequently asked questions
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