MaxScale is an open-source, highly scalable, and transparent load balancing solution for MySQL and MariaDB databases. It acts as a proxy between applications and databases, authenticating clients, routing queries, and monitoring database nodes. MaxScale supports features like read/write splitting, connection load balancing, and filtering of queries through extensible plugin modules. Typical use cases include balancing read loads across database replicas and distributing connections among nodes in a Galera cluster.