Hooks: free, open-source webhook testing

We’ve been hard at work building the big 2.0 release with SMS, WhatsApp, Email, Zapier and Webhook event forwarding, but we got stuck on webhook testing. We want to make sure webhook delivery from API Alerts to your systems is bulletproof, and that means handling a lot of different response types and shapes.

The market is quite saturated with free webhook testing tools and most of them are great. But I wanted something slightly different for our test bench.

I wanted the ability to change the webhook response at will with different status codes and payloads. First minute everything is fine, next minute I want total chaotic responses. 404s, 500s, 301s, whatever. Then back to success. I wanted to answer: how should API Alerts react to differing webhook delivery statuses, and what action should we take?

We couldn’t find a tool that gave us that level of control without signing up, hitting limits, or paying for it. So we built our own.

It’s live at hooks.apialerts.com and the source is on GitHub.

Usage

Generate an endpoint, point your webhook sender at it, and every incoming request shows up in real time with full headers, body, and metadata.

curl -X POST https://hooks.apialerts.com/your-endpoint \
  -H "Content-Type: application/json" \
  -d '{"event": "invoice.paid", "amount": 49.99}'

The response is configurable. Choose from 200, 201, 400, 401, 403, 404, 500, 503, or a 35-second timeout. Each status code saves its own custom payload, so you can set up realistic responses for different scenarios and toggle between them without losing your work.

Self-host it

One command and you’re up and running:

docker compose up --build

That gives you the app and a database on port 8080. No sign-up, no external dependencies, fully self-contained on your own machine.

For production self-hosting, it works on any platform that runs containers. The repo has instructions for Docker Compose, standalone Docker with your own Postgres, VPS deployment, and Google Cloud Run.

Why open source

This isn’t our core product. API Alerts is a notification routing platform. Hooks is a dev tool we built for ourselves that turned out to be useful enough to share. Open-sourcing it means anyone can self-host it, contribute to it, or just read the code.

The stack

Intentionally simple. A single Go binary with embedded assets, server-rendered HTML with HTMX for interactivity, Tailwind CSS compiled without Node.js, and Postgres for storage. No JS framework, no bundler, no node_modules. The README has the full breakdown.

Try it at hooks.apialerts.com or browse the source on GitHub.