The HTTP interface described in this specification is unusual.

A more typical issuance flow would involve the passing of inputs in the content of message, describing the format with media types. The content of the response would include the response, again identified with a media type. A similar exchange might be used for redemption.

The current approach decorates a request with header fields. It appears as though that request could be made to any resource and for any purpose, meaning that it could serve a dual purpose. This is especially odd.

In addition to header fields, there also appears to be some notion that the request will have query parameters appended, with public or private data being passed in predefined parameters. This is totally unnecessary, as the site has complete control over the URL and can encode that information - or much more - as a result.

See also #221.