Webhook Request Inspector
Get a URL that captures incoming webhook requests, shows headers and bodies live, checks signatures, and forwards them to your localhost.
Economics
- Pricing example
- $9 for 50,000 captured requests with 30-day retention (free: 100 requests a day, 24-hour retention)
- Daily math
- 2-3 packs a day x $9 = $18-27/day.
- Target if you hit the daily math
- Target: $550 - $800 / month if the daily math is hit
Audience and urgency
Audience: Developers integrating payment, messaging and SaaS webhooks.
Urgency: Debugging webhooks means guessing what the provider actually sent. Developers need to see the raw request, verify the signature and replay it locally without deploying each change.
MVP scope
- ✓ Unique capture URLs that store method, path, query, headers and body
- ✓ Live request list (server-sent events) with pretty JSON and raw views
- ✓ Signature check helper: paste the signing secret and verify common HMAC schemes in the browser
- ✓ Small CLI that forwards captured requests to localhost and replays any request
- ✓ Custom response status/body per URL; credit packs via Stripe
Omitted features
- - Do NOT keep requests beyond the retention period
- - Do NOT position it as a production webhook relay
- - Do NOT store signing secrets on the server
Suggested stack
- Frontend
- Next.js + Tailwind CSS
- Backend or API
- Node server (Fly.io or Cloud Run) with Postgres; SSE for live updates; Node CLI published to npm
- Payments
- Stripe Checkout (credit packs)
- Hosting
- Fly.io or Cloud Run for the capture server; Vercel for the dashboard
Repository metadata
- Blueprint ID
webhook-request-inspector- Category ID
dev_tools- Monetization ID
usage_pack
Day-one distribution
Channels
- Reddit r/webdev and r/node (follow rules)
- dev.to tutorial on debugging webhook signatures
- Hacker News 'Show HN'
Reddit strategy
Share a guide on the 5 most common webhook signature mistakes and the free tier.
Cold outreach or directory hook
List on developer tool directories with an honest comparison to free alternatives.
Search keywords
webhook tester, inspect webhook requests, forward webhook to localhost
One-shot master prompt
Build a "Webhook Inspector" with a Node capture server, a Next.js dashboard and a CLI.
Core requirements:
1. Capture server: ANY /h/{id}/* stores method, path, query, headers, body (max 1 MB), source IP and timestamp in Postgres; responds with the configured status and body for that endpoint.
2. Dashboard: create endpoints, live request list via server-sent events, detail view with pretty JSON, raw body, headers table, and copy-as-curl.
3. Signature helper running in the browser: paste secret, choose scheme (HMAC-SHA256 hex/base64 over raw body, with or without timestamp prefix), and compare with a header value. Secrets never sent to the server.
4. CLI `npx hookinspect forward <endpoint-id> --to http://localhost:3000` that subscribes to new requests and re-sends them, plus `replay <request-id>`.
5. Retention job deletes requests after 24 hours (free) or 30 days (paid). Stripe Checkout packs ($9 per 50,000 requests).Comparable products
Published 2026-10-08.
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