It's open source. https://github.com/discourse/discourse

    Discourse implements a variety of open source tech. You may wish to familiarize yourself with the various components that Discourse is built on, in order to be an effective contributor:

    Languages/Frameworks

    Ruby on Rails - Our back end API is a Rails app. It responds to requests RESTfully and responds in JSON.
    Ember.js - Our front end interface is an Ember.js app that communicates with the Rails API.
    Databases

    PostgreSQL - Our main data store is Postgres.
    Redis - We use Redis for our job queue, rate limiting, as a cache and for transient data.