---
title: "Post Billing Setup"
method: POST
path: "/v1/billing/setup"
tags: ["billing"]
---

# Post Billing Setup

`POST /v1/billing/setup`

## Request

- Base URL: `https://api.lithtrix.ai` (the document declares no server; this is the origin it was published from)
- URL: `https://api.lithtrix.ai/v1/billing/setup`
- Auth: none declared

**Retired (Arc 37 Option A)** — Stripe tier subscriptions are no longer available.

Use ``POST /v1/billing/credits/checkout`` for slider credit purchases.

## Headers

- `authorization` string, nullable

## Request body

- BillingSetupRequest: Client-provided Stripe PaymentMethod ID.
  - `payment_method_id` string, required: Stripe pm_... token
  - `tier` 'starter' | 'pro': Paid tier to subscribe to: "starter" or "pro".

## Response `200`

Successful Response

- unknown

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/lithtrix/apis/lithtrix-api.md) · [All operations](https://skmtc.dev/lithtrix/apis/lithtrix-api/llms.txt) · [OpenAPI document](https://skmtc.dev/lithtrix/apis/lithtrix-api/revisions/be5de51bf4f8?raw)