---
title: "Start a card checkout (Polar)"
method: POST
path: "/v1/premium/checkout"
tags: ["Premium and prices"]
---

# Start a card checkout (Polar)

`POST /v1/premium/checkout`

## Request

- Base URL: `https://api.memestack.ai`
- URL: `https://api.memestack.ai/v1/premium/checkout`
- Auth: HTTP bearer

Card sales are sold by Polar as merchant of record (spec 2026-10-04 §4.3). Answers the Polar checkout URL to send the buyer to; the order is applied to the account when Polar's webhook confirms payment. Dark (404, before auth) unless card payments are switched on and the product is sold by card — see `card` on /v1/premium/products. Requires a fresh account. Rate limited 10/min/user.

## Request body

- object
  - `product` 'supporter_30d' | 'credits_100' | 'api_builder_30d' | 'api_growth_30d' | 'api_scale_30d' | 'api_calls_10k', required

## Response `200`

The checkout session.

- object
  - `url` string, uri

## Other responses

- `401`: Authentication required.
- `404`: Card checkout is not available for this product.
- `409`: ALREADY_SUBSCRIBED — the account already has an active card subscription (manage it from the portal).
- `502`: CHECKOUT_UNAVAILABLE — Polar did not answer.

---

[API](https://skmtc.dev/memestack/apis/memestack-api.md) · [All operations](https://skmtc.dev/memestack/apis/memestack-api/llms.txt) · [OpenAPI document](https://skmtc.dev/memestack/apis/memestack-api/revisions/9d3a19565f75?raw)