🌟Free & Open-Source In-Memory Databases
Valkey: The primary, community-driven open-source successor to Redis. Backed by the Linux Foundation and major tech companies (like AWS, Google, and Oracle), it is fully free under the BSD license and serves as a high-performance in-memory key-value store.
👉 Official Valkey Project Website [1, 2, 3]
KeyDB: A high-performance, fully open-source fork of Redis that is multithreaded. It can achieve significantly higher throughput than single-threaded engines by fully utilizing all available CPU cores.
👉 Official KeyDB Website [1]
Dragonfly: A modern, ultra-fast in-memory data store built using a novel multi-threaded architecture. It is designed to scale vertically to millions of operations per second per instance while remaining fully compatible with Redis and Memcached APIs.
👉 Official Dragonfly Website [1, 2, 3]
Memcached: A classic, highly performance-optimized distributed memory object caching system. It is simple, lightweight, and completely free under the permissive BSD license, designed to speed up dynamic web applications by alleviating database load.
👉 Official Memcached Website [1, 2, 3]
Apache Ignite: A robust, distributed in-memory computing platform. It acts as an in-memory data grid, cache, and high-performance transactional database that can optionally persist data to disk.
👉 Official Apache Ignite Website [1, 2, 3, 4, 5]
H2 Database: A very fast, open-source SQL database engine written in Java. It is primarily used in its in-memory mode for rapid local developer testing and embedded application development.
👉 Official H2 Database Website [1, 2, 3, 4, 5]