Answer one payment
using System.Net.Http.Headers;var client = new HttpClient();var request = new HttpRequestMessage{ Method = HttpMethod.Post, RequestUri = new Uri("https://api.slflo.com/api/integration/v1/payments/pay_01J9/ack"), Headers = { { "Idempotency-Key", "example" }, { "Authorization", "Bearer <token>" }, }, Content = new StringContent("{ \"external_number\": \"SO-0012345\", \"external_ref\": \"SO-0012345\", \"message\": null, \"outcome\": \"ACCEPTED\", \"reason_code\": null }") { Headers = { ContentType = new MediaTypeHeaderValue("application/json") } }};using (var response = await client.SendAsync(request)){ response.EnsureSuccessStatusCode(); var body = await response.Content.ReadAsStringAsync(); Console.WriteLine(body);}HttpRequest request = HttpRequest.newBuilder() .uri(URI.create("https://api.slflo.com/api/integration/v1/payments/pay_01J9/ack")) .header("Idempotency-Key", "example") .header("Authorization", "Bearer <token>") .header("Content-Type", "application/json") .method("POST", HttpRequest.BodyPublishers.ofString("{ \"external_number\": \"SO-0012345\", \"external_ref\": \"SO-0012345\", \"message\": null, \"outcome\": \"ACCEPTED\", \"reason_code\": null }")) .build();HttpResponse<String> response = HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofString());System.out.println(response.body());const url = 'https://api.slflo.com/api/integration/v1/payments/pay_01J9/ack';const options = { method: 'POST', headers: { 'Idempotency-Key': 'example', Authorization: 'Bearer <token>', 'Content-Type': 'application/json' }, body: '{"external_number":"SO-0012345","external_ref":"SO-0012345","message":null,"outcome":"ACCEPTED","reason_code":null}'};
try { const response = await fetch(url, options); const data = await response.json(); console.log(data);} catch (error) { console.error(error);}curl --request POST \ --url https://api.slflo.com/api/integration/v1/payments/pay_01J9/ack \ --header 'Authorization: Bearer <token>' \ --header 'Content-Type: application/json' \ --header 'Idempotency-Key: example' \ --data '{ "external_number": "SO-0012345", "external_ref": "SO-0012345", "message": null, "outcome": "ACCEPTED", "reason_code": null }'Kept at the version it answered: a payment that changes later is pending again. Needs payments:write. Send an Idempotency-Key header; a retry with the same key and body answers the first answer again, with Idempotent-Replayed: true.
Authorizations
Section titled “Authorizations”Parameters
Section titled “Parameters”Path Parameters
Section titled “Path Parameters”Slflo’s id of the payment (receipt), from the payment feed.
Example
pay_01J9Header Parameters
Section titled “Header Parameters”Your key for this write, at most 100 characters (an order id or journal id works well). Required on every write; kept 7 days. Same key and body: the first answer again. Same key, other body: 422 IDEMPOTENCY_KEY_REUSED.
Request Bodyrequired
Section titled “Request Bodyrequired”object
Example
{ "external_number": "SO-0012345", "external_ref": "SO-0012345", "message": null, "outcome": "ACCEPTED", "reason_code": null}Responses
Section titled “Responses”Answer one payment
object
object
object
Example
{ "data": { "ack": { "acked_at": "2026-10-05T10:42:00Z", "acked_version": 18343, "external_number": "SO-0012345", "external_ref": "SO-0012345", "message": null, "outcome": "ACCEPTED", "reason_code": null }, "id": "ord_01J9X", "number": "SO-000123", "result": "applied", "status": "ERP_CONFIRMED", "version": 18343 }}default
Section titled “default”An error: the code says what, retryable whether to try again.
object
object
Stable code, e.g. SCOPE_MISSING, UNKNOWN_REFERENCE.
Field-level problems: {field, code}.
object
What happened and how to fix it.
Quote it to support; it finds the server log.
Whether the same call may succeed later.
Example
{ "error": { "code": "SCOPE_MISSING", "details": [], "message": "This client does not hold the invoices:read scope.", "request_id": "req_01J9X4Q7T2M8P3NRT6V5WZ", "retryable": false }}
