Overview
Redis is the industry standard for in-memory data storage, traditionally operating in a single-threaded mode. KeyDB is a high-performance fork of Redis designed to eliminate single-threading bottlenecks through a multi-threaded architecture.
| Parameter | Redis | KeyDB |
|---|---|---|
| Architecture | Single-threaded core (IO-threads since v6) | Multi-threaded core |
| License | RSALv2 / SSPLv1 (since 2024) | BSD 3-Clause |
| Compatibility | Original protocol | Full Redis API compatibility |
| Scaling | Horizontal (Cluster) | Vertical and Horizontal |
| Snapshotting | Fork-based (Copy-on-write) | Flash-based / Multi-threaded |
Performance
Redis processes commands sequentially. On a single core, performance reaches 100-150k operations per second. While Redis 6 introduced io-threads to speed up network I/O, the command execution logic remains single-threaded.
KeyDB distributes command execution across multiple threads. In benchmarks on 16-core instances, KeyDB demonstrates 3-7x higher throughput than Redis, exceeding 700,000+ OPS on a single node. This allows for reducing the number of cluster nodes while maintaining the same load capacity.
Configuration & complexity
KeyDB is a drop-in replacement. The main difference in the configuration file is the server-threads parameter. In Redis, thread configuration is limited to io-threads, which do not affect the execution of the commands themselves.
# KeyDB config
server-threads 4
active-replication yesKeyDB also supports active replication (multi-master), simplifying the setup of high-availability schemes compared to Redis Sentinel.
When to choose what
Redis: Choose for maximum stability, usage in managed cloud services (AWS ElastiCache, Google MemoryStore), or if the current workload does not saturate a single CPU core.
KeyDB: Choose to minimize infrastructure footprint, handle large datasets on powerful multi-core servers, or when a permissive BSD license is required without BSL/RSAL restrictions.
Cost / licensing
In March 2024, Redis transitioned to non-free RSALv2 and SSPLv1 licenses, restricting cloud providers from offering Redis as a service. KeyDB remains under the BSD license, making it preferable for open-source projects and custom cloud deployments.
Ecosystem & integrations
Redis has a massive community, support for all existing SDKs, and integration with all monitoring systems. KeyDB is fully compatible with Redis clients (jedis, redis-py, go-redis), so migration requires no application code changes.
Verdict
- Redis is the choice for standard Enterprise solutions where vendor support and a long-proven codebase are critical.
- KeyDB is the choice for high-load systems where vertical scalability and high request density per server are prioritized.