API reference

A REST API with predictable resource-oriented URLs, JSON bodies, HTTP Basic auth, and standard status codes. Base URL https://api.yusker.com/v1.

Conventions

  • All amounts are integers in the smallest currency unit (cents).
  • Timestamps are ISO-8601 UTC. IDs are prefixed by type (ID, MU, PI, TR).
  • Send Idempotency-ID on writes to make retries safe.
  • Errors return a JSON body with code and message; 2xx success, 4xx client error, 5xx Yusker error.

Identities

POST/v1/identities
GET/v1/identities/{id}
POST/v1/identities/{id}/merchants
Identities guide →

Merchants

GET/v1/merchants/{id}
GET/v1/merchants
Merchants guide →

Payment Instruments

POST/v1/payment_instruments
GET/v1/payment_instruments/{id}
Payment Instruments guide →

Transfers

POST/v1/transfers
GET/v1/transfers/{id}
POST/v1/transfers/{id}/reversals
Transfers guide →

Webhooks

POST/v1/webhooks
GET/v1/webhooks
Webhooks guide →

Errors

{
  "code": "invalid_request",
  "message": "amount must be a positive integer",
  "field": "amount"
}
  • 400 invalid_request — malformed or missing parameters.
  • 401 unauthenticated — missing or invalid API key.
  • 402 charge_declined — the issuer declined the card.
  • 403 forbidden — the key lacks access to the resource.
  • 404 not_found — no such resource.
  • 409 conflict — idempotency or state conflict.
  • 429 rate_limited — slow down and retry with backoff.