Apps similar to Pivotal GemFire include MongoDB, which has a free version. Other options are Redis, CouchDB, DiceDB and Valkey. In-memory Databases like Pivotal GemFire are a crowded field, with more than 25 alternatives for Linux, Mac, Windows, self-hosting and the web.
TidesDB is a fast and efficient key value storage engine library written in C. The underlying data structure is based on a log-structured merge-tree (LSM-tree).
