Watercoolr

Example:

Create a channel:

→ POST /channels
← { 'id':'2d0128d' }

Add subscribers:

→ POST /subscribers data={ 'channel':'2d0128d', 'url':'http://api.otherservice.com/your-message-handler' }
← { 'status': 'OK' }

Post messages:

you → POST /messages data={ 'channel':'2d0128d', 'message':'hey guys!' }
   us → POST http://api.otherservice.com/your-message-handler data='hey guys!'
   ...for every subscriber...
← { 'status': 'OK' }

Run it locally on your own server, or using http://watercoolr.nuklei.com