A versioned REST API over the whole system, with idempotency keys, cursor pagination, signed webhooks and a sandbox.
Not sure which parts you need?
Most people need about a third of this and are not sure which third — and nobody works that out from a list. Create a free account today and look around; it costs nothing and you do not have to talk to us first.
Yes — the interface is a client of the same API, so there is no capability reachable through the screen that is unreachable through the wire. That is the structural version of the promise, rather than a policy that could quietly lapse.
Today we issue them — tell us what you are building and we will set up a client and a sandbox. Self-serve registration from a developer dashboard is being built and is not shipped yet.