RxDB (Reactive Database) is a NoSQL-database for Node.js and the browser. It is based on the popular database PouchDB, but adds additional features such as reactive query results and support for IndexedDB in the browser.

RxDB is designed to be easy to use and integrate into modern web applications. It uses the ReactiveX (RxJS) library to provide an observable interface for data changes, which allows developers to easily build reactive, real-time applications.

RxDB is also designed to be flexible and scalable, with support for multiple storage engines (such as IndexedDB, WebSQL, and LevelDB) and the ability to replicate data with other RxDB instances or external databases. It can be used in a variety of contexts, including as a standalone database or as a local data store for applications that need offline support.