Postgres supports JSON and JSONB for a couple of years now. The support for JSON-functions landed in version 9.2. These functions let Postgres server to return JSON serialized data. This is a handy feature. Consider a case; Python client fetches 20 records from Postgres. The client converts the data returned by the server to tuple/dict/proxy. The application or web server converts tuple again back to JSON and sends to the client. The mentioned case is common in a web application. Not all API...
