Basic JSON REST API using the Flask web microframework.

jsonrestapi.py

import os 
import Flask, jsonify

@app.route('/')
def index(): 
  json = jsonify(response="Hello World!")
  return json 

if __name__ == '__main__':
  app.debug = True 
  port = int(os.environ.get('PORT', '5000')) 
  app.run(host='0.0.0.0', port=port)