Redis, Hazelcast, Aerospike, SAP HANA, and Apache Ignite are the most popular tools in the category “In-Memory Databases”. “Performance” is the primary reason developers pick Redis over its competitors, while “High Availibility” is the reason why Hazelcast was chosen.
An open-source in-memory document oriented database
An extremely simple Golang-based in-memory KV store
An open source in-memory database for enabling real-time web apps
An open-source in-memory data manager (By Alibaba)
Fast, powerful, massively scalable time-series database
Immutable database and Datalog query engine for Clojure, ClojureScript and JS
Open source time series database for IoT and Big Data
The In-Memory computing solution to scale your applications
Open source lighting fast key-value database with advanced features
Concurrent Maps, Sets and Queues backed by disk storage or off-heap-memory
High-performance database for geospatial and realtime geofencing applications
An open-source distributed database, caching and processing platform
High performance, in-memory storage engine for time series data (by Facebook)
A fast, embeddable, in-memory key/value database for Go with custom indexing and geospatial support