Idempotency

Create-checkout is idempotent so enrolment wizards can safely retry.

Key selection

Prefer the Idempotency-Key header
Otherwise StudentPay uses {provider_code}:{provider_order_id}

Example:

POST /v1/provider-checkouts
Idempotency-Key: ONFIT-ENROLMENT-12345
Authorization: Bearer ...

Behaviour

If an Opportunity already exists for the same provider and provider order ID (or checkout ID), StudentPay returns the existing checkout with:

{
  "success": true,
  "idempotent_replay": true,
  "idempotency_key": "ONFIT-ENROLMENT-12345"
}

No additional Contact / Opportunity / DDA / Agreement records are created.

Confirm

Confirmation already short-circuits when the Opportunity checkout status is already confirmed and reuses an existing accepted Payment Plan Agreement where present.