Webhooks are the backbone of modern API integrations. Whether you're working with Stripe payments, GitHub actions, or Twilio SMS, knowing how to intercept and test webhooks locally is critical.
1. The Localhost Challenge
When a 3rd party service tries to send a webhook (an HTTP POST request) to your application, it needs a public URL. Since your local development server runs on localhost:3000, the external service cannot reach it.
2. The Solution: Webhook Catchers
Instead of using complex tunneling tools like Ngrok that require installation and expose your local machine to the internet, you can use a pure Webhook Catcher.
A catcher gives you a permanent, public URL that instantly records any incoming payload.
3. How to use mockly.me for Webhooks
- Head over to the Webhook Tester on mockly.me.
- Generate a unique URL (e.g.,
https://mockly.me/hook/abc-123). - Paste that URL into your Stripe/GitHub/Shopify dashboard.
- Trigger an event and watch the payload appear on your screen in real-time.
You can inspect the headers, the exact JSON body, and even see the query parameters passed along. It's the absolute fastest way to see what an API is going to send your code before you write the handler!