---
search:
  tags:
    - Checkout API Key
    - POST
seo:
  description: >-
    Start checkout session with external ID and custom URLs Reference for the
    POST /api/checkout/buy-plan endpoint in the Insy API API.
sidebar:
  badge: POST
  label: Start checkout session with external ID and custom URLs
title: Start checkout session with external ID and custom URLs
type: openapi-operation
---
<Operation source="developers-api-reference" id="buy-plan" />