poste.io

Full version administration demo

https://poste.io/admin/login#admin@poste.io;admin

Username: admin@poste.io
Password: admin

Live REST API demo with sandbox

https://admin@poste.io:admin@poste.io/admin/api/doc

Username: admin@poste.io
Password: admin

Sample REST API script in PHP:
https://gist.github.com/analogic/8fcdc87ce8d4d8adfed9