A simple sinatra server that accepts a POST with JSON content.

sinatra-server.rb

# To make this server publicly available on the inter-webs while running from localhost, use ngrok, which can be found here:
# https://ngrok.com/download.  Follow the installation instructions for ngrok and start it up:
#
#   ./ngrok 4567 # (or whatever port you want to listen on).
#
# ngrok will spit out an ugly but unique URL.  After ngrok starts up, you should be able to POST to the sinatra server:
#
#   http://6eee766f.ngrok.com/payload
require 'sinatra'
require 'json'

post '/payload' do
  push = JSON.parse(request.body.read)
  puts "I got some JSON: #{push.inspect}"
end