Show HN: WebhookBox – Test webhooks instantly, no signup required

I've been using online webhook tools for years, but always thought they felt slow and cluttered. Figured I could build something cleaner with modern tools.

Spent the past week building WebhookBox.

How it works:

Go to webhookbox.io, click the button, you get a URL like webhookbox.io/w/abc123. Send webhooks to it. They show up instantly. That's it.

No signup needed for testing (anonymous, 24hr retention). If you do sign up, you get persistent URLs, history, API access, etc.

What I built:

- Real-time request viewer (Supabase Realtime is honestly pretty slick for this - saved me from building custom WebSocket infra)

- See headers, body, query params - everything

- Custom responses if you need to return specific status codes or test error handling

- Export as cURL/Python/JS/whatever

Tech decisions:

Next.js + Supabase + Vercel edge functions. Used edge to get ~50-80ms global response times. Postgres JSONB for flexible payload storage. Rate limiting via Vercel KV to prevent abuse (100 req/hour per anonymous endpoint).

Free tier is 3 endpoints, 100 requests/month. Pro is $9/mo if you need more.

Thinking about adding webhook forwarding to localhost next - basically a WebSocket tunnel to forward webhooks directly to your dev server, skip ngrok entirely. Would that be useful or is the current approach good enough?