CouchDB is described as 'Apache CouchDB is a distributed, fault-tolerant and schema-free document-oriented database accessible via a RESTful HTTP / JSON API. It includes incremental map / reduce mechanics for queries and keeps data safe with an append-only datastore' and is a relational database in the development category. There are more than 50 alternatives to CouchDB for a variety of platforms, including Linux, Windows, Mac, Self-Hosted and Web-based apps. The best CouchDB alternative is PostgreSQL, which is both free and Open Source. Other great apps like CouchDB are MySQL Community Edition, MongoDB, MariaDB and Redis.