API Platform

Accounts

Represent balances and positions that value moves between.

Counterparties

Represent the external parties an account transacts with.

Payment Instructions

Represent a request to move value, tracked through explicit states.

Settlements

Represent the settlement of one or more instructions against sources.

Ledger Entries

Represent immutable double-entry postings behind every balance.

Events

Represent state changes emitted for subscription and replay.

# Illustrative design sketch — not a live endpoint.
# Base URL is a placeholder; the API is not publicly available.
POST https://api.example-railix.invalid/v1/payment_instructions
Authorization: Bearer <sandbox_key>
Content-Type: application/json

{
  "amount": "1500.00",
  "currency": "USD",
  "source_account": "acct_29fk...",
  "counterparty": "cpty_7bd2...",
  "idempotency_key": "pi_2f0a1c9e"
}

# Illustrative response
{
  "id": "pmt_8Kd0aX2mQ",
  "object": "payment_instruction",
  "state": "screening",
  "amount": "1500.00",
  "currency": "USD",
  "created_at": "2026-01-01T00:00:00Z"
}

1. 01

   Subscribe

   An integrator registers an endpoint and selects the event types it wishes to receive.

2. 02

   Event Emitted

   A state change produces an event recorded to an append-only log with a stable identifier.

3. 03

   Signed Delivery

   The event is delivered with a signature so the receiver can verify authenticity and integrity.

4. 04

   Retry With Backoff

   Failed deliveries are retried on an increasing backoff schedule to absorb transient outages.

5. 05

   Replay From Log

   Integrators can replay events from the log to recover from downtime without data loss.

Planned event names (illustrative): payment.created, payment.screened, payment.settled, payment.failed, ledger.entry.posted.