# Fast forward a test subscription (/api/subscriptions/fast-forward-subscription)

`POST https://api.comecero.com/api/v1/subscriptions/{subscription_id}/fast_forward`

For testing renewals. Moves the end of the current billing period (and of the trial, if any) to `seconds_from_end` seconds from now. When that time comes, the renewal runs as normal: an invoice is made and the customer's saved payment method is charged (in test mode), and renewal emails and events go out. Only works with a test token on a test subscription that is `active` or `trial`, and not when the period already ends sooner. Secret and trusted tokens may call it; a limited token may not (`403`). No body.

## Parameters

- `seconds_from_end` (query): How many seconds from now the current period should end. Default `0` (now). Maximum `86400` (one day).
- `expand` (query): Comma-separated child objects to return in full instead of as a URL, for example `customer,payments`. Use dot notation for nested objects (`items.product`), up to four levels deep. A single object takes up to 12 paths; a list takes up to 2, applied to every item. Extra paths are dropped without an error. See [Expanding objects](https://docs.comecero.com/docs/basic-concepts/expanding-objects).
- `show` (query): Comma-separated fields to return; all others are left out. Use dot notation for child fields (`customer.email`). You cannot send `show` and `hide` together (`400`). See [Customizing output](https://docs.comecero.com/docs/basic-concepts/customizing-output).
- `hide` (query): Comma-separated fields to leave out of the response. Use dot notation for child fields (`customer.email`). You cannot send `show` and `hide` together (`400`). See [Customizing output](https://docs.comecero.com/docs/basic-concepts/customizing-output).
- `formatted` (query): When `true`, the object also has a `formatted` child with amounts and dates as display text in the shopper's language and currency (for example `$19.99` or `November 7, 2026`). The default is `false`. See [Localized formatting](https://docs.comecero.com/docs/basic-concepts/localized-formatting).

Responses: 200, 400, 401, 403, 404, 422, 500.

Full schemas: operation `fast_forward_subscription` in /openapi.json.