---
title: "Billing Checkout"
method: GET
path: "/billing/checkout"
tags: ["billing"]
---

# Billing Checkout

`GET /billing/checkout`

## Request

- Base URL: `https://mcp.sentinelx.app` (the document declares no server; this is the origin it was published from)
- URL: `https://mcp.sentinelx.app/billing/checkout`
- Auth: none declared

Start a checkout for `tier` (?tier=plus&billing=monthly|annual).

Requires a dashboard session; redirects to login if absent. On success
303-redirects to Polar's hosted checkout URL.

## Query parameters

- `tier` string, required
- `billing` string

## Cookies

- `sentinelx_dash_session` string, nullable

## Response `200`

Successful Response

- unknown

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/sentinelx/apis/sentinelx-hub.md) · [All operations](https://skmtc.dev/sentinelx/apis/sentinelx-hub/llms.txt) · [OpenAPI document](https://skmtc.dev/sentinelx/apis/sentinelx-hub/revisions/d1f84924795e?raw)