Stars
Apache Arrow is the universal columnar format and multi-language toolbox for fast data interchange and in-memory analytics
RTBkit is an open-source software package that allows you to create and deploy a Real Time Bidder for display advertising.
SSDB - A fast NoSQL database, an alternative to Redis
For developers, who are building real-time data-driven applications, Redis is the preferred, fastest, and most feature-rich cache, data structure server, and document and vector query engine.
A python library for implementing a recommender system
C library for estimating cardinality in streams for which it is infeasible to store all events in memory