---
title: "Start authorization flow"
method: POST
path: "/v3/payments/{id}/authorization-flow"
tags: ["Payments"]
---

# Start authorization flow

`POST /v3/payments/{id}/authorization-flow`

Start the authorization flow for a payment.

This API can be called:
- using the `resource_token` associated with the payment you are trying to fetch;
- using a backend bearer token.

## Path parameters

- `id` string, required — Unique ID for the Payment

## Headers

- `Idempotency-Key` string
- `Tl-Signature` string
- `X-Forwarded-For` string
- `X-Device-User-Agent` string

## Response `200`

Payment

## Other responses

- `400` — Invalid Request
- `401` — Unauthenticated
- `403` — Forbidden
- `404` — Payment Not Found
- `409` — Conflict
- `422` — Idempotency-Key Reuse
- `500` — Unknown Error

---

[API](https://skmtc.net/truelayer/apis/authentication-server.md) · [All operations](https://skmtc.net/truelayer/apis/authentication-server/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/truelayer/authentication-server/versions/5f6051515b2c/schema)