Documentation Index
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Retry writes safely with an Idempotency-Key header.
Idempotency-Key header with a write. If you retry with the same key and the same body, you get the original response back and the work doesn’t run twice. This stops a retried finalize from spending a second invoice number.
curl -X POST https://invoice.horizonpay.co/api/v1/invoices/in_Pb2Xk7Mv4Qs9Lr1Wd6Tn3Fh8/finalize \
-H "Authorization: Bearer $INVOICE_AI_API_KEY" \
-H "Idempotency-Key: 8e0f4b1c-6f55-4c37-9d0b-2a7f5f0c9e21"
// The SDK adds a key to every POST and reuses it on retries.
// Pass your own to make a call safe across process restarts:
await invoiceai.invoices.finalize('in_Pb2Xk7Mv4Qs9Lr1Wd6Tn3Fh8', {
idempotencyKey: 'finalize-order-1234',
})
# The SDK adds a key to every POST and reuses it on retries.
# Pass your own to make a call safe across process restarts:
client.invoices.finalize(
"in_Pb2Xk7Mv4Qs9Lr1Wd6Tn3Fh8",
idempotency_key="finalize-order-1234",
)
| Endpoint | Idempotency-Key |
|---|---|
POST /invoices, POST /invoice-items | Required |
POST /invoices/{id}/finalize, /send, /pay, /void | Required |
Other POST endpoints | Optional |
GET, PATCH, DELETE | Ignored |
| Situation | Result |
|---|---|
| Required but not sent | 428 idempotency_key_required. Nothing runs. |
| Same key and body, first request succeeded | The stored response, with Idempotent-Replayed: true. |
| Same key, first request still running | 409 conflict. Retry shortly. |
| Same key, different method, path or body | 422 idempotency_mismatch |
| Same key, first request failed | The request runs again. Failures aren’t stored. |