---
title: "Start a hosted checkout for a plan not already held (tier, message class, and billing interval)"
method: POST
path: "/billing/checkout"
tags: ["Account and billing"]
---

# Start a hosted checkout for a plan not already held (tier, message class, and billing interval)

`POST /billing/checkout`

## Request

- Base URL: `https://sendhq.cc/api/v1`
- URL: `https://sendhq.cc/api/v1/billing/checkout`
- Auth: API key in cookie `sendhq_session_v2`
- TypeScript: <https://skmtc.dev/sendhq/apis/sendhq-api/docs/billing/checkout/post.ts> (a function with typed inputs; its response is checked against the schema)

Start a hosted checkout for a plan not already held (tier, message class, and billing interval)

## Request body

- object
  - `plan_key` string, required

## Response `200`

Successful response

- object
  - `url` string, uri, required
  - `session_id` string, required

## Other responses

- `400`: Invalid request
- `401`: Missing or invalid authentication
- `402`: A paid entitlement is required for this recipient or feature
- `403`: The workspace, domain, policy, or suppression state forbids the operation
- `404`: Tenant-scoped resource not found
- `409`: Resource state or idempotency conflict
- `413`: Attachment count or bytes exceed the accepted limit
- `422`: Request validation or suppression check failed
- `423`: Sending is paused for this sender identity or workspace; the message gives the reason and how to appeal
- `429`: A monthly, daily, or trial usage limit was reached
- `500`: Unexpected server error
- `502`: An upstream provider operation failed
- `503`: A required provider or signing configuration is unavailable
- `default`: An error response using SendHQ's standard JSON envelope

---

[API](https://skmtc.dev/sendhq/apis/sendhq-api.md) - [All operations](https://skmtc.dev/sendhq/apis/sendhq-api/llms.txt) - [OpenAPI document](https://skmtc.dev/sendhq/apis/sendhq-api/revisions/98e39e48cb9a?raw)