Look up a transfer with the bank

POSThttps://api.checkslip.com/api/slips/lookup

API key

Send the QR text read from the slip, or the slip image, and we ask the sending bank for the transfer it holds and return that data. We return what the bank has; the decision to accept the payment is yours, against your own order. The result is in outcome, e.g. FOUND, NOT_FOUND, DUPLICATE, PENDING. One credit is used only when outcome is FOUND. We never store the slip image, only the QR text. Images up to 10 MB and 50 megapixels, JPEG, PNG or WebP only (HEIC, GIF and PDF get 422 invalid-file, no credit). Always send an Idempotency-Key; a retry with the same value returns the same result and never charges twice. Needs an API key with slip:lookup.

Parameters

Field	In	Type	Required
`Idempotency-Key`	header	`string`	no

Request body

application/json Also accepts: multipart/form-data

Field	Type	Required
`qr`	`string`	yes
`client_reference`	`string \| null`	no

Responses

200 `application/json`

Field	Type	Required
`request_id`	`string (uuid)`	yes
`outcome`	`FOUND \| NOT_FOUND \| DUPLICATE \| PENDING`	yes
`checked_at`	`string (date-time)`	yes
`slip`	`Slip \| SlipSummary`	yes
`duplicate_of`	`DuplicateOf`	no
`duplicate_of.request_id`	`string (uuid)`	yes
`duplicate_of.checked_at`	`string (date-time)`	yes
`client_reference`	`string \| null`	no

202 `application/json`

Field	Type	Required
`request_id`	`string (uuid)`	yes
`outcome`	`FOUND \| NOT_FOUND \| DUPLICATE \| PENDING`	yes
`checked_at`	`string (date-time)`	yes
`slip`	`Slip \| SlipSummary`	yes
`duplicate_of`	`DuplicateOf`	no
`duplicate_of.request_id`	`string (uuid)`	yes
`duplicate_of.checked_at`	`string (date-time)`	yes
`client_reference`	`string \| null`	no

Possible errors

400401402403409413415422429500503

An error as Problem Details. All codes are listed at Error codes

curl https://api.checkslip.com/api/slips/lookup \
  -H "Authorization: Bearer $CHECKSLIP_API_KEY" \
  -H "Idempotency-Key: order-1042-slip-1" \
  -H "Content-Type: application/json" \
  -d '{"qr":"00330006000001010306902126302105340875102TH9104F86F"}'

const res = await fetch("https://api.checkslip.com/api/slips/lookup", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.CHECKSLIP_API_KEY}`,
    "Idempotency-Key": "order-1042-slip-1",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    qr: "00330006000001010306902126302105340875102TH9104F86F",
  }),
});
const data = await res.json();

import os

import requests

res = requests.post(
    "https://api.checkslip.com/api/slips/lookup",
    headers={
        "Authorization": f"Bearer {os.environ['CHECKSLIP_API_KEY']}",
        "Idempotency-Key": "order-1042-slip-1",
    },
    json={
        "qr": "00330006000001010306902126302105340875102TH9104F86F",
    },
)
data = res.json()

{
  "request_id": "0192d4e0-7c1a-7b3e-9f00-1a2b3c4d5e6f",
  "outcome": "FOUND",
  "checked_at": "2026-10-29T10:41:02+07:00",
  "slip": {
    "trans_ref": "630210534087",
    "transferred_at": "2026-10-29T10:33:30+07:00",
    "amount": {
      "satang": 5000,
      "currency": "THB"
    },
    "sender": {
      "bank": {
        "code": "KKP",
        "bot_code": "069",
        "name_th": "ธนาคารเกียรตินาคินภัทร",
        "name_en": "Kiatnakin Phatra Bank"
      },
      "name_th": "นาย สมชาย ใ",
      "name_en": "MR. SOMCHAI J",
      "account": "0439"
    },
    "receiver": {
      "kind": "BANK_ACCOUNT",
      "bank": {
        "code": "GSB",
        "bot_code": "030",
        "name_th": "ธนาคารออมสิน",
        "name_en": "Government Savings Bank"
      },
      "name_th": "นางสาว สมหญิง ร",
      "name_en": "MISS SOMYING R",
      "account": "9681"
    }
  }
}

{
  "request_id": "0192d4e0-7c1a-7b3e-9f00-1a2b3c4d5e70",
  "outcome": "FOUND",
  "checked_at": "2026-10-29T10:41:02+07:00",
  "slip": {
    "trans_ref": "630210534088",
    "transferred_at": "2026-10-29T10:33:30+07:00",
    "amount": {
      "satang": 125050,
      "currency": "THB"
    },
    "sender": {
      "bank": {
        "code": "KKP",
        "bot_code": "069",
        "name_th": "ธนาคารเกียรตินาคินภัทร",
        "name_en": "Kiatnakin Phatra Bank"
      },
      "name_th": "นาย สมชาย ใ",
      "name_en": "MR. SOMCHAI J",
      "account": "0439"
    },
    "receiver": {
      "kind": "BILL_PAYMENT",
      "bank": null,
      "name_th": "บริษัท ตัวอย่าง จำกัด",
      "name_en": null,
      "account": null
    }
  }
}

{
  "request_id": "0192d4e2-1111-7c00-8000-000000000002",
  "outcome": "DUPLICATE",
  "checked_at": "2026-10-29T10:45:10+07:00",
  "slip": {
    "trans_ref": "630210534087",
    "sender_bank": {
      "code": "KKP",
      "bot_code": "069",
      "name_th": "ธนาคารเกียรตินาคินภัทร",
      "name_en": "Kiatnakin Phatra Bank"
    },
    "receiver_bank": {
      "code": "GSB",
      "bot_code": "030",
      "name_th": "ธนาคารออมสิน",
      "name_en": "Government Savings Bank"
    },
    "transferred_at": "2026-10-29T10:33:30+07:00",
    "amount": {
      "satang": 5000,
      "currency": "THB"
    }
  },
  "duplicate_of": {
    "request_id": "0192d4e0-7c1a-7b3e-9f00-1a2b3c4d5e6f",
    "checked_at": "2026-10-29T10:41:02+07:00"
  }
}

{
  "request_id": "0b6c2f5e-8a41-4d1e-9c3a-5f7e2d18a6b4",
  "outcome": "FOUND",
  "checked_at": "2026-11-05T09:30:00+07:00",
  "slip": {
    "trans_ref": "630210534087",
    "transferred_at": "2026-10-29T10:33:30+07:00",
    "amount": {
      "satang": 5000,
      "currency": "THB"
    },
    "sender": {
      "bank": {
        "code": "KKP",
        "bot_code": "069",
        "name_th": "ธนาคารเกียรตินาคินภัทร",
        "name_en": "Kiatnakin Phatra Bank"
      },
      "name_th": "นาย สมชาย ใ",
      "name_en": "MR. SOMCHAI J",
      "account": "0439"
    },
    "receiver": {
      "kind": "BANK_ACCOUNT",
      "bank": {
        "code": "KKP",
        "bot_code": "069",
        "name_th": "ธนาคารเกียรตินาคินภัทร",
        "name_en": "Kiatnakin Phatra Bank"
      },
      "name_th": "ร้าน ทดสอบ",
      "name_en": "TEST S",
      "account": "0439"
    },
    "names_erased": true
  },
  "duplicate_of": {
    "request_id": "0b6c2f5e-8a41-4d1e-9c3a-5f7e2d18a6b4",
    "checked_at": "2026-11-05T09:30:00+07:00"
  },
  "client_reference": "ORDER-10023"
}

Parameters#

Request body#

Responses#

200 application/json#

202 application/json#

Possible errors#