URI and Versioning

We hope to improve it over time, the API changes won't always be backwards compatible, so we're going to version the API. This first iteration will live at https://api.payssion.com/v2/ to differentiate from the Payssion v1 version.

Please never rely on the order of the returned fields to do business processing. Only the removal of a non-optional field or alteration of an existing field will be considered incompatible changes. Clients should gracefully handle additional fields they don't expect and simply ignore them.