---
title: "UCP Cancel credit checkout"
method: POST
path: "/api/v1/commerce/ucp/checkout-sessions/{id}/cancel"
tags: ["commerce"]
---

# UCP Cancel credit checkout

`POST /api/v1/commerce/ucp/checkout-sessions/{id}/cancel`

## Request

- Base URL: `https://singlefax.com`
- URL: `https://singlefax.com/api/v1/commerce/ucp/checkout-sessions/{id}/cancel`
- Auth: API key in header `Authorization`

Requires a bearer SingleFax API key with credits:checkout. Buyer pays at hosted Stripe continue_url; GET confirms ledger fulfillment. No inline payment handlers. See /commerce.md.

## Path parameters

- `id` string, required

## Headers

- `UCP-Agent` string, required
- `Idempotency-Key` string, required

## Request body

- object

## Response `200`

Protocol checkout state

- CheckoutJson (unresolved $ref)

## Other responses

- `4XX`: Invalid request, authorization, unsupported feature or state conflict
- `5XX`: Payment provider or service unavailable

---

[API](https://skmtc.dev/singlefax/apis/singlefax-api.md) · [All operations](https://skmtc.dev/singlefax/apis/singlefax-api/llms.txt) · [OpenAPI document](https://skmtc.dev/singlefax/apis/singlefax-api/revisions/f6fdbfac1e25?raw)