---
title: "ACP: create a checkout session"
method: POST
path: "/checkout_sessions"
tags: ["commerce"]
---

# ACP: create a checkout session

`POST /checkout_sessions`

## Request

- Base URL: `https://mitosislabs.ai`
- URL: `https://mitosislabs.ai/checkout_sessions`
- Auth: none required

Agentic Commerce Protocol (OpenAI + Stripe) checkout, snapshot 2026-04-17; the 2025-09-29 `items[].id` body is accepted too. Prices real catalog items and returns totals, links and a continue_url. Completion escalates to the account owner (see /checkout_sessions/{id}/complete). Guide: /developers/guides/agentic-commerce

## Headers

- `API-Version` string
- `Idempotency-Key` string
- `Request-Id` string

## Request body

- CheckoutSessionCreate
  - `line_items` object[]
    - `item` object, required
      - `id` string, required
    - `quantity` integer
  - `items` object[]: 2025-09-29 shape, accepted for compatibility
    - `id` string, required
    - `quantity` integer
  - `buyer` object
    - `first_name` string
    - `last_name` string
    - `email` string, email
    - `phone_number` string

## Response `201`

Checkout session

- CheckoutSession
  - `id` string, required
  - `protocol` object
    - `version` string
  - `status` 'not_ready_for_payment' | 'ready_for_payment' | 'requires_escalation' | 'completed' | 'canceled' | 'expired', required
  - `currency` string, required
  - `buyer` object
  - `line_items` object[], required
  - `fulfillment_options` object[]
  - `fulfillment_option_id` string
  - `totals` object[], required
    - `type` string, required
    - `display_text` string, required
    - `amount` integer, required
  - `messages` object[], required
  - `links` object[], required
    - `type` string, required
    - `url` string, uri, required
  - `continue_url` string, uri: Where the account owner completes payment
  - `expires_at` string, date-time
  - `capabilities` object

## Other responses

- `400`: ACP error
- `422`: Idempotency conflict
- `429`: Rate limited

---

[API](https://skmtc.dev/mitosislabs/apis/mitosis-public-api.md) · [All operations](https://skmtc.dev/mitosislabs/apis/mitosis-public-api/llms.txt) · [OpenAPI document](https://skmtc.dev/mitosislabs/apis/mitosis-public-api/revisions/c82bbc6785c1?raw)