---
title: "Start a credit top-up checkout"
method: POST
path: "/billing/usage-top-up/checkout"
tags: ["Billing"]
---

# Start a credit top-up checkout

`POST /billing/usage-top-up/checkout`

## Request

- Base URL: `https://api.cactal.ai/v1`
- URL: `https://api.cactal.ai/v1/billing/usage-top-up/checkout`
- Auth: HTTP bearer

Starts hosted checkout to add prepaid `credits` (minimum 400). Top-up credits never expire and are spent after the monthly allowance. Pass `idempotencyKey` so retries do not duplicate purchases; exact duplicates may return a conflict. Requires active billing and the organization owner.

## Request body

- object
  - `organizationId` string, required
  - `credits` integer, required
  - `successUrl` string
  - `idempotencyKey` string

## Response `200`

Checkout result for the top-up.

- object
  - `paymentUrl` string, nullable, required: Hosted checkout URL to redirect the customer to. `null` when the change was applied directly without a payment step.

## Other responses

- `400`: Validation failed. The response `message` names the first invalid field.
- `401`: Missing, invalid, expired, or revoked API key.
- `403`: The authenticated principal lacks the required capability.
- `404`: The resource does not exist or is outside the principal’s access scope.
- `409`: The request conflicts with the current state of the resource.
- `429`: Rate limit exceeded. Retry after the number of seconds in the `Retry-After` header.

---

[API](https://skmtc.dev/cactal/apis/cactal-api.md) · [All operations](https://skmtc.dev/cactal/apis/cactal-api/llms.txt) · [OpenAPI document](https://skmtc.dev/cactal/apis/cactal-api/revisions/9cd0fb5eacdd?raw)