order-already-existsCopy Anchor Link

HTTP 409. The externalOrderId in your request already belongs to a different order on this connection.

{
  "type": "https://developers.supliful.com/errors/order-already-exists",
  "title": "Order already exists",
  "status": 409,
  "detail": "externalOrderId PARTNER-1001 already belongs to order 3f6c1a52-0c3d-4a1e-9f21-5d0f6b8e77a4.",
  "orderId": "3f6c1a52-0c3d-4a1e-9f21-5d0f6b8e77a4"
}

externalOrderId is how you look an order up with GET /v1/orders/{orderId}, so two orders cannot share one. The existing order is in orderId.

Why a retry can land hereCopy Anchor Link

A retry that reuses the original request's key is recognised and answered with the original order. This error means the key was different, so we cannot tell a retry from a second order. The usual causes:

• The key changed between attempts. The first request relied on externalOrderId as the key and a retry added an Idempotency-Key header, or your HTTP client generates a fresh header per attempt.
• Your system reused an order number. Two distinct orders carry the same identifier on your side.

How to fix itCopy Anchor Link

• If this is a retry, the order was already placed. Fetch it with orderId and carry on. Keep the key stable across attempts so later retries return 200 instead.
• If it is a new order, give it its own externalOrderId.

Do not retry the same request: it will keep failing identically.