Memcached vs Valkey

Memcached: The original multi-threaded, dead-simple distributed memory cache for key-value blobs. Valkey: The Linux Foundation's BSD-licensed fork of Redis, now the default engine on AWS and Google Cloud.

key differences

Memcached is built for larger datasets (≤ 1 PB) than Valkey (≤ 10 TB).
Horizontal scaling is manual in Memcached and native in Valkey.
Transactions: Memcached offers none ACID; Valkey offers limited.
Only Valkey has transactions, geospatial, stored procedures, pub/sub, durable persistence.

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 valkey for

+Replacing Redis OSS without license concerns
+Application caching and session storage
+Rate limiting, counters and leaderboards
+Pub/sub fan-out and Streams-based queues

best at · Cache, Sessions, Queue

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

ValkeyThe Linux Foundation's BSD-licensed fork of Redis, now the default engine on AWS and Google Cloud.

overview

Primary model

Key-Value

Also supports

–

Type

Database engine

Status

Active

Developer

Memcached community (originally Danga Interactive)

Valkey project (Linux Foundation)

First release

2003

2024

Latest version

1.6.45 (Jul 9, 2026)

9.1.3 (Oct 26, 2026)

License

Open source (permissive)BSD 3-Clause

Free tier

✓

popularity

WhichDB Score

50.6

58.0

Rank

#25

#16

GitHub stars

14.3K

27.5K

Stack Overflow questions

5.2K

scale & guarantees

Comfortable data size

Large (≤ 1 PB)

Medium (≤ 10 TB)

Horizontal scaling

Manual

Native

Multi-region

None

Read replicas

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, Oracle Cloud, Aiven, DigitalOcean, Akamai

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

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 Valkey: FAQ

What is the difference between Memcached and Valkey?

Memcached: The original multi-threaded, dead-simple distributed memory cache for key-value blobs. Valkey: The Linux Foundation's BSD-licensed fork of Redis, now the default engine on AWS and Google Cloud. Memcached is built for larger datasets (≤ 1 PB) than Valkey (≤ 10 TB). Horizontal scaling is manual in Memcached and native in Valkey. Transactions: Memcached offers none ACID; Valkey offers limited.

When should I choose Memcached over Valkey?

Choose Memcached for read-through caching of database query results; rendered page and fragment caching; and session storage when losing sessions is acceptable. Choose Valkey for replacing Redis OSS without license concerns; application caching and session storage; and rate limiting, counters and leaderboards.

Is Memcached or Valkey more popular?

Valkey ranks #16 on the WhichDB Score (58.0/100) and Memcached ranks #25 (50.6/100). Popularity is not fit: check the requirements that matter for your project.

Are Memcached and Valkey open source?

Yes. Memcached is open source. License: BSD 3-Clause. Yes. Valkey is open source. License: BSD 3-Clause.