TokuMX vs Vitess: What are the differences?

What is TokuMX? A high-performance, concurrent, compressing, drop-in replacement engine for MongoDB. TokuMX is a drop-in replacement for MongoDB, and offers 20X performance improvements, 90% reduction in database size, and support for ACID transactions with MVCC. TokuMX has the same binaries, supports the same drivers, data model, and features of MongoDB, because it shares much of its code with MongoDB.

What is Vitess? It is a database clustering system for horizontal scaling of MySQL. It is a database solution for deploying, scaling and managing large clusters of MySQL instances. It’s architected to run as effectively in a public or private cloud architecture as it does on dedicated hardware. It combines and extends many important MySQL features with the scalability of a NoSQL database.

TokuMX and Vitess can be primarily classified as "Databases" tools.

TokuMX is an open source tool with 679 GitHub stars and 90 GitHub forks. Here's a link to TokuMX's open source repository on GitHub.