Memcached vs Redis

Memcached: The original multi-threaded, dead-simple distributed memory cache for key-value blobs. Redis: The in-memory data structure server that became the default cache, now with search, JSON and vectors built in.

key differences

Licensing: Memcached is open source (permissive) (BSD 3-Clause); Redis is open source (copyleft) (Tri-license: AGPLv3, RSALv2 or SSPLv1 (Redis 8+)).
Memcached is built for larger datasets (≤ 1 PB) than Redis (≤ 10 TB).
Horizontal scaling is manual in Memcached and native in Redis.
Transactions: Memcached offers none ACID; Redis offers limited.
Only Redis has transactions, secondary indexes, full-text search, vector search, geospatial.

choose memcached for

+Read-through caching of database query results
+Rendered page and fragment caching
+Session storage when losing sessions is acceptable
+Very large, horizontally sharded look-aside cache tiers

best at · Cache, Sessions

choose redis for

+Application and database query caching
+Session storage and user tokens
+Rate limiting and distributed locks
+Leaderboards and counters

best at · Cache, Sessions, Queue

MemcachedThe original multi-threaded, dead-simple distributed memory cache for key-value blobs.

RedisThe in-memory data structure server that became the default cache, now with search, JSON and vectors built in.

overview

Primary model

Key-Value

Also supports

–

Document, Vector, Time-Series, Search Engine

Type

Database engine

Status

Active

Developer

Memcached community (originally Danga Interactive)

Redis Ltd.

First release

2003

2009

Latest version

1.6.45 (Jul 9, 2026)

8.10.3 (Oct 26, 2026)

License

Open source (permissive)BSD 3-Clause

Open source (copyleft)Tri-license: AGPLv3, RSALv2 or SSPLv1 (Redis 8+)

Free tier

✓

popularity

WhichDB Score

50.6

84.3

Rank

#25

GitHub stars

14.3K

77.1K

Stack Overflow questions

5.2K

25.4K

scale & guarantees

Comfortable data size

Large (≤ 1 PB)

Medium (≤ 10 TB)

Horizontal scaling

Manual

Native

Multi-region

None

Active active

ACID

None

Limited

Consistency

Eventual

Schema

Schemaless

Architecture

In memory, Single node, Client server

In memory, Single node, Primary replica, Distributed, Client server

deployment

Self-hosted

✓

Vendor-managed cloud

—

✓

Serverless

—

Embedded

—

Edge

—

Clouds

AWS, Google Cloud, Alibaba Cloud, Tencent Cloud

AWS, Google Cloud, Azure, DigitalOcean, Heroku, Render

capabilities

Transactions

—

✓

Joins

—

Secondary indexes

—

✓

Full-text search

—

✓

Vector search

—

✓

Geospatial

—

✓

JSON

—

✓

Change data capture

—

Triggers

—

Stored procedures

—

✓

Materialized views

—

TTL / expiry

✓

Pub/Sub

—

✓

Columnar storage

—

In-memory

✓

Durable persistence

—

✓

Compression

—

Encryption at rest

—

Role-based access

—

✓

Time travel

—

Branching

—

Online schema changes

—

Streaming ingest

—

✓

Offline sync

—

Runs in WebAssembly

—

interfaces

Query languages

Memcached text/meta protocol

Redis commands (RESP), Lua, Redis Query Engine (FT.*)

Client languages

C, Java, Python, PHP, Go, JavaScript, Ruby, C#

Python, Java, JavaScript, Go, C#, Rust, Ruby, PHP

Best for

Cache, Sessions

Cache, Sessions, Queue, Pub/Sub

Add more to this comparison Not sure either fits? Try smart match

Memcached vs Redis: FAQ

What is the difference between Memcached and Redis?

Memcached: The original multi-threaded, dead-simple distributed memory cache for key-value blobs. Redis: The in-memory data structure server that became the default cache, now with search, JSON and vectors built in. Licensing: Memcached is open source (permissive) (BSD 3-Clause); Redis is open source (copyleft) (Tri-license: AGPLv3, RSALv2 or SSPLv1 (Redis 8+)). Memcached is built for larger datasets (≤ 1 PB) than Redis (≤ 10 TB). Horizontal scaling is manual in Memcached and native in Redis.

When should I choose Memcached over Redis?

Choose Memcached for read-through caching of database query results; rendered page and fragment caching; and session storage when losing sessions is acceptable. Choose Redis for application and database query caching; session storage and user tokens; and rate limiting and distributed locks.

Is Memcached or Redis more popular?

Redis ranks #2 on the WhichDB Score (84.3/100) and Memcached ranks #25 (50.6/100). Popularity is not fit: check the requirements that matter for your project.

Are Memcached and Redis open source?

Yes. Memcached is open source. License: BSD 3-Clause. Yes. Redis is open source. License: Tri-license: AGPLv3, RSALv2 or SSPLv1 (Redis 8+).