---
title: "How do I test subscriptions with the test clock?"
description: "A test clock lets you fast-forward time in test mode so you can see a subscription's renewals, trial ending, and dunning without waiting real days."
url: "/docs/developers/how-do-i-test-subscriptions-with-the-test-clock/"
category: "Developers"
---

A **test clock** lets you fast-forward time in test mode so you can watch a subscription behave over weeks or months in seconds — its renewals, a trial ending, an instalment charging, and dunning on a failed charge — without waiting for real dates to arrive.

## What to test

- **A renewal** — advance past the billing date and confirm the next charge and `SubscriptionCharged` event fire.
- **A trial ending** — advance to the trial-end date and confirm the first charge (or auto-cancel) and the `SubscriptionTrialEnded` event.
- **Instalments** — step through an annual instalment plan to see each monthly charge and `SubscriptionInstallmentCharged`.
- **Dunning** — with a failing test card, advance past a charge to see the retry and `SubscriptionPastDue`.

## How to use it

Create a subscription in **test mode**, then advance the test clock to the dates you want to exercise. All of this stays in test data — no real charges — so you can validate your webhook handling for the full subscription lifecycle before going live. See [How do subscriptions and recurring billing work?](/docs/accepting-payments/how-do-subscriptions-and-recurring-billing-work/)

## Related

- [How do free trials work?](/docs/accepting-payments/how-do-free-trials-work/)