---
title: "Pre Auth"
method: POST
path: "/v3/transactions/auth"
tags: ["Transactions"]
---

# Pre Auth

`POST /v3/transactions/auth`

This API endpoint initiates a pre-authorization command to a terminal. The final approval/decline result is delivered asynchronously to the callbackURL.

## Headers

- `Authorization` string, required
- `X-Idempotency-Key` string, uuid, required

## Request body

- AuthRequest
  - `tenantId` string, required — The last 12 digits of the merchant identifier (MID).
  - `terminalId` string, required — 10-digit terminal serial number.
  - `transactionId` string, required — Client-generated transaction identifier used for reconciliation.
  - `amount` object, required — Message amount providing total, subtotal, currency, tip, and tax.
    - `total` number, required — The total amount of the transaction, in cents.
    - `subtotal` number, required — The transaction amount prior to tip and tex, in cents.
    - `currency` string, required — The three-letter alphabetic ISO currency code.
    - `tip` number, nullable — The tip amount, in cents
    - `tax` number, nullable — The tax amount, in cents.
  - `printReceipt` 0 | 1 | 2 | 3, required — Allowed values: <br> 0 – No receipt<br> 1 – Print merchant receipt<br> 2 – Print customer receipt<br> 3 – Print both merchant and customer receipts
  - `callbackURL` string, required — HTTPS endpoint that receives the asynchronous callback payload.
  - `metadata` object

## Response `200`

Transaction Initiated

- SuccessResponse
  - `traceId` string, uuid — Correlation identifier matching the initial API response traceId
  - `response` object
    - `status` 'SUCCESS' — Whether the original request was successful.

## Other responses

- `400` — Invalid Request

---

[API](https://skmtc.net/payarc/apis/payarc-sandbox.md) · [All operations](https://skmtc.net/payarc/apis/payarc-sandbox/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/payarc/payarc-sandbox/versions/face82bdd778/schema)