What is Valkey

Valkey is a high-performance key-value in-memory database with rich data structures, ideal for caching, message queues, session storage, and more.

Background: Valkey is an open-source fork of Redis (BSD license), maintained by the Linux Foundation community after Redis changed its license. It is fully API-compatible and can be used as a drop-in replacement.

Key Features

Rich Data Structures: String, Hash, List, Set, Sorted Set, Stream, Bitmap, HyperLogLog, and more
In-Memory + Persistence: Data operates primarily in memory, with both RDB snapshots and AOF log persistence
High Performance: Single-threaded model avoids lock contention; a single instance can handle 100K+ QPS
Publish/Subscribe: Built-in Pub/Sub messaging with pattern-based subscriptions
Lua Scripting: Atomic Lua script execution for transactional complex operations
Cluster Mode: Native data sharding and automatic failover support
Module System: Extend functionality via C modules (e.g., RediSearch, RedisJSON)

Common Use Cases

Scenario	Description	Data Structure
Caching	Reduce database load, accelerate hot data reads	String / Hash
Session Store	Distributed session management with TTL auto-expiry	String / Hash
Leaderboard	Real-time ranking with score updates and range queries	Sorted Set
Message Queue	Lightweight task queue with consumer groups	Stream / List
Distributed Lock	Mutual exclusion for shared resources across nodes	String (SET NX)
Counter	Real-time stats for article views, likes, etc.	String (INCR)

Architecture Overview

Valkey uses a single-threaded event loop model (I/O threads are optionally multi-threaded). The core architecture includes:

Event Loop: I/O multiplexing based on epoll/kqueue for client connections and command execution
Memory Management: Uses the jemalloc allocator to reduce fragmentation; controls memory limits via maxmemory policies
Persistence Engine: RDB generates snapshots via fork child process; AOF records every write command and replays on restart
Replication: Asynchronous master-replica replication with cascading and partial resynchronization (PSYNC)

Quick Start

After installation, connect via the command-line client and run basic operations:

bashCopy

$ valkey-cli
127.0.0.1:6379> SET mykey "Hello Valkey"
OK
127.0.0.1:6379> GET mykey
"Hello Valkey"
127.0.0.1:6379> INCR counter
(integer) 1
127.0.0.1:6379> INCR counter
(integer) 2
127.0.0.1:6379> TTL mykey
(integer) -1

Security Notice: By default, Valkey has no password and listens on all network interfaces. In production, always configure requirepass and bind parameters.

Relationship with Redis

Valkey is a direct fork of Redis 7.2, maintaining full command and data format compatibility. Key differences:

Valkey is managed by the Linux Foundation under an OSI-approved open-source license
Community-driven development with a more transparent contribution process
Ongoing performance optimizations — 5-10% improvement over Redis 7.2 in some scenarios
All existing Redis clients and tools can connect to Valkey seamlessly

Installation Guide