pg_jbuilder is a tool to dump database queries directly to a JSON object or array. It uses PostgreSQL's JSON functions ([array_to_json and row_to_json](http://www.postgresql.org/docs/9.3/static/functions-json.html)) to serialize the JSON completely bypassing ActiveRecord/Arel. This gives a large speed boost compared to serializing the JSON inside of Ruby/Rails. It is perfect for creating JSON APIs with very low response times.