Iro is a non blocking server for sending a message to a bunsh of recipients. It can handle different types of message and can be extended easially. It was initially written for sms backend of castorticker.de. There are diffrent backends are supported by Iro. Iro helps you for these kinds of tasks: You want to send a message to some recipient over a different backend, than for other recipients. Or you want to define fallback strategies: If one messages can't be send over this backend use another. Because Iro also knows users, you can create bills for different clients.
A backend is a provider, that actually sends the message.
Just download ${code} see also installtion instruction under Installing Iro.
If you want just use iro see API Documentation. For extending iro see the developer documenation.