09 — Roadmap · 12
Gateway reachability
PATH FINDER
A member on an external rail can reach destinations that are not its customers. Every resolver answer carries `standing`. This implementation emits `holder`. Answering as a gateway is reserved: `PATH-FINDER.Gateway` is not declared. A gateway is advertised in discovery and called directly. It does not appear in a SONAR answer.
- Target
- Triggered, not scheduled
- Year
- 2028
- Window
- H1
- Status
- reserved
The index says who holds. The register says who reaches.
What already exists
The field and the discovery block. Every resolver answer carries `standing`, and the value emitted here is `holder`. The `gateway` block in discovery is present and empty. A caller that already knows the member uses the relationship profile: no directory, no membership.
What is reserved
Answering as a gateway. A gateway answer carries the intermediary’s terms, `commitment: null`, and the reserved fields `fees`, `expires_at` and `address: null`. A gateway does not appear in a SONAR answer. An unknown key and a hidden key produce the same response, including on a range a member declares it can reach.
What it is for
Members of a network are mutually reachable. Parties outside it are not listed in the directory. Gateway reachability is how a member states which external rails it can pay, without those destinations becoming index entries.
What it is not
Admission to the rail. A gateway still joins PIX or UPI under those schemes’ own rules. And not a rail profile — a gateway needs one to speak the rail, exactly as a holder does, which is a separate piece of work. Nor Crossway: Crossway reads another network’s registry and offers no terms; a gateway offers its own terms to carry the payment.