Apache CouchDB is a distributed, fault-tolerant and schema-free document-oriented database accessible via a RESTful HTTP/JSON API.
- A document database server, accessible via a RESTful JSON API.
- Ad-hoc and schema-free with a flat address space.
- Distributed, featuring robust, incremental replication with bi-directional conflict detection and management.
It is not
- A relational database.
- A replacement for relational databases.
- An object-oriented database. Or more specifically, meant to function as a seamless persistence layer for an OO programming language.