The x-callback-url spec was written by Greg Pierce, of Agile Tortoise. Ideas, contributions and comments have been provided by many — including encouragement early on by Marco Arment, Justin Williams and others.
The spec is intended to evolve with contributions from other developers, and I’d love to hear input. Follow the blog or the @xcallbackurl on Twitter account to keep up with changes, and new apps supporting x-callback-url.
If you have any questions about the protocol or implementation in your apps, please feel free to contact info _at_ x-callback-url _dot_ com.