Shotover Proxy is an open source, high performance L7 data-layer proxy for controlling, managing and modifying the flow of database requests in transit. 

It can be used to solve many different operational and interoperability challenges for teams where polyglot persistence (many different databases) is common.

Shotover can be deployed in many different ways including as an application sidecar, as a standalone proxy, and as a sidecar to a database. 

Users can support relevant xDS APIs, hot-reloads and a dynamic configuration API, additional sources such as DynamoDB and PostgreSQL.

They can also add support for rate limiting, explicit back-pressure mechanisms, additional distributed algorithm transform primitives, and more. 

Additional details on the project are available here