Testing

Sandbox is the default environment — completely isolated from production.

Test Flow

// 1. Create customer
const customerId = `test_${Date.now()}`
const customer = await commet.customers.create({
  email: 'test@example.com',
  id: customerId,
})

// 2. Create subscription
const subscription = await commet.subscriptions.create({
  customerId,
  planCode: 'pro',
})

// 3. Pay with test card at checkoutUrl

// 4. Track usage
await commet.usage.track({
  customerId,
  feature: 'api_calls',
})

Dev Tools Panel

A floating widget that appears on all sandbox pages. The Test Clock tab is available everywhere. The Test Data tab (address and card presets) only appears on checkout pages.

Test Clock

Simulate future dates to test billing cycles, renewals, and prorations without waiting for real time to pass.

Current Time — displays the simulated time in UTC, or the real time if no simulation is active.

Set Time — pick a future date from a calendar. Time can only move forward and cannot be reverted.

Quick Advance — jump forward by a preset amount:

Run Billing Cron — manually trigger billing processing at the simulated time. This processes renewals, generates invoices, and applies usage charges.

Example workflow: advance 1 month to reach the next billing cycle, then run billing cron to generate renewal invoices and verify charges.

Test Data

The Test Data tab automates checkout form filling with valid test data for 60+ countries. Open it from the Dev Tools panel on any sandbox checkout page.

Address autofill — select a country and the checkout address form is automatically filled with a valid name, street, city, postal code, and phone number for that country. No need to type anything manually.

Country-specific test cards — after selecting a country, the panel shows the test card number that matches that country. Click to copy. Expiry and CVC are always 12/34 and 123.

Failure scenarios — generic cards are available to test error handling: declined payments, insufficient funds, expired cards, and 3D Secure authentication. See the tables below.

Test cards by country

Failure scenarios

3D Secure

Production

const commet = new Commet({
  apiKey: process.env.COMMET_PRODUCTION_KEY!,
  environment: 'production',
})