Why a provider cannot call localhost directly
A webhook provider runs outside your network. The address http://127.0.0.1:3000 only exists on your computer, so a provider such as Stripe or GitHub cannot open a connection to it. You need a public receiving address and a controlled way to deliver the event to your development server.
A tunnel can expose a development service, but an event-forwarding workflow is often easier to reason about: first capture the public request, then send a copy to the local URL you choose.
Use a capture, inspect and forward loop
Configure the provider to send to a dedicated endpoint. When an event arrives, inspect its method, path, headers and body before forwarding it. This gives you a stable event record even if your local server is offline or your first implementation returns an error.
Run a local listener, then connect a CLI forwarder to the endpoint. The forwarder delivers new events to an explicit local URL, such as http://127.0.0.1:4000/hooks/payments. Your application receives the original request data plus forwarding metadata that identifies the captured event.
Checks worth making before you trust a local test
A successful HTTP response is useful, but it is not enough. Confirm that the request path is the one your handler expects, the event type is parsed correctly, and signature verification uses the provider's original body rather than a changed serialization.
- Log the event ID so you can trace a local result back to the captured request.
- Test a retry or duplicate delivery to confirm your handler is idempotent.
- Use realistic provider payloads instead of only hand-written JSON fixtures.
- Keep local forwarding opt-in and point it only at a local URL you control.
Preserve a request before changing code
When a production delivery exposes a bug, preserve the original request first. You can then make a focused change, run it locally, and replay the exact event instead of trying to reconstruct the payload from memory. This shortens debugging cycles and makes the fix easier to verify.