
hookVM
Webhook.site
ngrok
Hooklistener
Webhooks.cc
Hookmetry
RequestBin
Debug webhooks on localhost in seconds. Receive, inspect, edit, and replay webhooks directly to your localhost using a CLI and WebSockets. No tunneling hacks. Free to start.

The modern platform for creating, sharing, and collaborating on AI prompts. Advanced version control and real-time testing.

Website, pricing, platforms and company facts side by side.
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| Website | hookreplay.dev | diffyn.com |
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What each product offers, as listed by its team.


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As answered by people managing HookReplay.dev and Diffyn.
HookReplay.dev's answer
Three things most webhook tools don't do: 1- Replay the same webhook unlimited times 2- Edit payloads before replaying (test edge cases) 3- Keep a full history of every webhook received HookReplay does all three, plus real-time forwarding like ngrok.
Diffyn's answer:
Addresses workflow and change management on LLM prompts, provide teams with traceability and visualization of tests across multiple models, provide deeper understading into efficiency of these prompts.
HookReplay.dev's answer
With ngrok, every code change means triggering another webhook. Add a log? Trigger again. Set a breakpoint? Too late, it timed out. Trigger again. With HookReplay, you trigger once. Then replay 100 times while you debug. Same webhook. Same payload. Unlimited attempts to get your code right. That's not a small difference — it's hours saved per debugging session.
Diffyn's answer:
Diffyn is the platform that specializes on both change management and multi-model analysis.
HookReplay.dev's answer
ASP.NET Core for the backend, PostgreSQL for storage, WebSockets for real-time forwarding to the CLI. The CLI is built in .NET and distributed via npm — runs on macOS, Windows, and Linux. Nothing fancy. Boring tech that works.
Diffyn's answer:
React, Next.js, POSTGRESQL
HookReplay.dev's answer
Developers who integrate third-party webhooks Stripe, Shopify, GitHub, Twilio, Paddle, etc. Basically anyone who's ever clicked "Send test webhook" more times than they'd like to admit.
Diffyn's answer:
Professionals incorporating LLMs or AI tools in their workflow and wants to keep track of changes and test their prompts.
HookReplay.dev's answer
11pm on a Sunday. A customer's Stripe payment went through, but their subscription wasn't created. I needed to debug the webhook handler. Set up ngrok. Triggered a test payment. Added a log statement. Triggered again. Set a breakpoint — webhook timed out before I could step through. Triggered again. Changed the URL in Stripe because ngrok restarted. Triggered again. Three hours later, I found a typo in my event type check. I remember thinking: I just re-triggered the same webhook 40+ times. Why can't I just capture it once and replay it until I find the bug? That's the moment HookReplay was born. The tool I wished existed that night.
Diffyn's answer:
I started working on Diffyn when I notice that prompting has become an essential part of work across many industries. While there are version control platofrms like github, they are not designed for just prompt management are can be overkill such applications, it is also not integrated natively with various LLMs and relevant tools for users to validate ideas and visualise results properly.
HookReplay.dev's answer
Still early — just launched. Currently used by indie developers and small teams debugging Stripe and Shopify integrations. No big logos yet. Focused on building a great product first.
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