Apache CouchDB is a free and open-source NoSQL database developed by the Apache Software Foundation. It can be used as a single-node or clustered database. CouchDB server stores its data in named databases, which contains documents with JSON structure. Each document consists of a number of fields and attachments. Fields can include text, numbers, lists, booleans, more. CouchDB includes a RESTful HTTP API that allows you to read, create, edit, and delete database documents.