3. Query Server

The Query server is an external process that communicates with CouchDB by JSON protocol through stdio interface and processed all design functions calls: views, shows, lists and more.

The default query server is written in JavaScript, running via Mozilla SpiderMonkey. You can use other languages by setting a Query server key in the language property of a design document or the Content-Type header of a temporary view. Design documents that do not specify a language property are assumed to be of type javascript.