07 — PIPs · PIP-0003
Rail profiles
Named mappings from PATH’s last mile onto rails that already settle — UPI, Pix, SEPA Instant.
- Number
- PIP-0003
- Status
- draft
- Type
- Networking
- Author
- PATH
- Date
- 2026-09-09
- Source
- On the register
Why
PATH does not replace an instant rail. It names the last mile — who, where, what is owed, who may act, whether it arrived — in a form another scheme can read. A rail profile is that mapping. Without a PIP, each integrator invents a private translation and two PATH addresses that should be able to meet, cannot.
A rail profile is not a `gateway`. A profile is vocabulary: which PATH object is which rail object. A gateway is whose terms an answer carries. A member settling its own customers over Pix uses the profile and is not a gateway. A gateway uses the profile as well.
What a profile is
A profile is a published table: PATH object → rail object. It is not a new pillar. It does not add a colour, a wallet, or a PATH rail. Liquidity stays reserved.
A profile includes the rows that cannot be translated. Omitting them is a non-conformity.
| PATH | Rail |
|---|---|
| PATH ID | The scheme’s customer reference, where one exists |
| PATH ADDRESS — capability | The rail identifier and the currencies the scheme carries |
| PATH ADDRESS — instruction | The scheme’s beneficiary formats, and its remittance field as `payment_reference` |
| PATH REQUEST | The claim the scheme already collects, through its request-to-pay service when it has one |
| PATH CONNECT | Who may instruct the scheme |
| PATH SETTLEMENT | The scheme’s own transaction identifiers, as `rail_references` types, quoted rather than replaced |
A profile fills the rail's entry in the rail register (PIP-0007): beneficiary_formats, rail_reference_types, payment_reference, request_overlay. Publishing it moves the rail from reserved to profiled.
First profiles
UPI, Pix, SEPA Instant. Each profile is a later PIP or an annex. This PIP only fixes that a profile is a document, that it is public, and that a network claiming a rail without publishing the table is non-conformant.
A profile is written when a member first touches that rail, not in advance of anyone using it.
What sits above or below a rail is described in that rail's profile, not as a rail of its own. SPI, the settlement system under Pix, is part of the pix profile. Wero is part of the sepa-inst profile. CoDi is the request-to-pay service of the spei profile.
Rail identifiers
Rail identifiers take one spelling, fixed by the rail register (PIP-0007): the scheme's short name, lower case, with a country suffix only on collision. A profile uses the register's identifier.
What it is not
It is not admission to those rails. PATH cannot seat a member at UPI. A club that wants to speak UPI still admits under its own rulebook, and the rail still admits under its own.