Slip verification

Two endpoints deal with slips:

Endpoint	Use it when	Effect
POST /v1/slips/verify	You want to know whether a slip is genuine and what it contains	Changes no payment
POST /v1/payins/{id}/slip	The payer has paid but the pay-in was not matched yet, and you want to confirm it with the slip	If it matches, the pay-in becomes succeeded and a webhook is sent

Verify a slip

POST /v1/slips/verify

Two request forms:

• JSON: send the text of the slip’s QR code in payload (max 2000 characters). Optionally add checkDuplicate: true to check whether the slip was used before.
• multipart/form-data: send the slip image (JPG or PNG, max 5 MB) as the only part, named file. Sign the hash of the file bytes; see multipart requests. (checkDuplicate is not available in this form.)

Node.js

import { readFile } from 'node:fs/promises';
import { api, signRequest } from './partner-api.mjs';

// 1) QR payload
const { data: byPayload } = await api('POST', '/v1/slips/verify', {
  payload: qrText,
  checkDuplicate: true,
});

// 2) Image: sign the file bytes, send only the `file` part
const bytes = await readFile('slip.jpg');
const form = new FormData();
form.append('file', new Blob([bytes], { type: 'image/jpeg' }), 'slip.jpg');
const res = await fetch('https://api.example.com/v1/slips/verify', {
  method: 'POST',
  headers: signRequest('POST', '/v1/slips/verify', bytes),
  body: form,
});
const { data: byImage } = await res.json();

PHP

// 1) QR payload
$result = partner_api('POST', '/v1/slips/verify', ['payload' => $qrText, 'checkDuplicate' => true])['data'];

// 2) Image: sign the file bytes, send only the `file` part
$path = '/v1/slips/verify';
$ch = curl_init('https://api.example.com' . $path);
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_HTTPHEADER => partner_sign('POST', $path, file_get_contents('slip.jpg')),
    CURLOPT_POSTFIELDS => ['file' => new CURLFile('slip.jpg', 'image/jpeg')],
    CURLOPT_RETURNTRANSFER => true,
]);
$result = json_decode(curl_exec($ch), true)['data'];
curl_close($ch);

Python

import requests
from partner_api import api, sign_request

# 1) QR payload
result = api("POST", "/v1/slips/verify", {"payload": qr_text, "checkDuplicate": True})["data"]

# 2) Image: sign the file bytes, send only the `file` part
with open("slip.jpg", "rb") as f:
    content = f.read()
r = requests.post("https://api.example.com/v1/slips/verify",
                  headers=sign_request("POST", "/v1/slips/verify", content),
                  files={"file": ("slip.jpg", content, "image/jpeg")}, timeout=60)
result = r.json()["data"]

The result

A failed check still returns HTTP 200. Look at verified and failureCode.

{
  "data": {
    "object": "slip_verification",
    "verified": true,
    "failureCode": null,
    "payload": "0041000600000101030040220...",
    "bankReference": "202601011234567890",
    "transferredAt": "2026-01-01T00:04:12.000Z",
    "amount": "150.37",
    "currency": "THB",
    "sender": {
      "bankCode": "SCB",
      "bankName": "Siam Commercial Bank",
      "accountNumber": "xxx-x-x4567-x",
      "accountName": "นาย สมชาย ส",
      "accountNameEn": "MR. SOMCHAI S"
    },
    "receiver": {
      "bankCode": "KBANK",
      "bankName": "Kasikorn Bank",
      "accountNumber": "xxx-x-x5432-x",
      "accountName": "บจก. ตัวอย่าง",
      "accountNameEn": "EXAMPLE CO., LTD."
    }
  },
  "requestId": "req_..."
}

failureCode	Meaning
slip_not_found	No transfer matches the slip
duplicate_slip	The slip was used before
amount_mismatch	The amount does not match
receiver_mismatch	The receiver does not match
invalid_image	The image could not be read or the file is invalid
invalid_payload	The payload is invalid
verification_unavailable	Temporarily unavailable; try again later

sender and receiver come from the bank. Some fields may be null or partly masked.

Testing with a test key

With a test key (pk_test_...) the slip is not checked with the bank and no quota is used. Results are simulated from the payload:

payload starts with	Result
TESTFAIL	verified: false, failureCode: "slip_not_found"
TESTDUP	verified: false, failureCode: "duplicate_slip"
anything else (or an image)	verified: true, amount 100.00 THB, bankReference TEST-REF-0000000000

Errors

HTTP	code	Meaning
400	parameter_missing	Neither payload (JSON) nor file (multipart) was sent
400	file_invalid	No file, not a JPG/PNG, or larger than 5 MB
400	parameter_unknown	The multipart body has parts other than file
422	slip_verification_unavailable, slip_verification_failed	The verification service has a problem; try again later
429	quota_exceeded	Your slip verification quota is used up; contact the team

Uploading a slip for a pay-in

POST /v1/payins/{id}/slip

Use it when the payer has transferred but the pay-in is still pending, for example when the payer sends you the slip. Send multipart/form-data with a single file part (JPG or PNG, max 5 MB) and sign the hash of the file bytes. See uploadSlip in the code samples.

{
  "data": {
    "object": "slip_upload",
    "matched": true,
    "slipStatus": "matched",
    "payin": { "object": "payin", "id": "pin_3f2b1c0d9e8f4a7b8c6d5e4f3a2b1c0d", "status": "succeeded", "...": "..." }
  },
  "requestId": "req_..."
}

• matched: true: the slip matches and the pay-in is now succeeded. The usual payin.succeeded webhook is sent.
• matched: false: not matched yet; check slipStatus and the pay-in’s status.

Caution

A slip can be used only once. A slip that was already used returns 409 slip_duplicate.

HTTP	code	Meaning
400	file_invalid	No file, not a JPG/PNG, or larger than 5 MB
404	resource_not_found	Unknown pay-in
409	payin_not_pending	The pay-in is no longer waiting for payment (succeeded, expired or canceled)
409	slip_duplicate	The slip was already used
422	slip_unreadable	The QR code on the slip could not be read; ask for a clearer image
422	slip_amount_mismatch	The slip amount differs from the pay-in’s amount
422	slip_receiver_mismatch	The receiving account differs from payTo
422	slip_verification_failed	The bank check failed
422	slip_verification_unavailable	Slip verification is temporarily off