patchbay.pub is a free web service you can use to implement things like static site hosting, file sharing, cross-platform notifications, webhooks handling, smart home event routing, IoT reporting, job queues, chat systems, bots, etc, all completely serverless and requiring no account creation or authentication. Most implementations need nothing but curl and simple bash snippets.

skor is a utility for Postgres which calls a webhook with row changes as JSON whenever an INSERT, UPDATE or DELETE event occurs on a particular table. You can drop the docker image next to your Postgres database instance and configure a webhook that will be called.

It works using a pg_notify trigger function and a tiny C program skor that listens to the notifications and calls the configured webhook with a JSON payload.

Use webtask for …
Serverless Applications

Run server-side code for your JavaScript and native applications. Just worry about your code.
Programmable Webhooks

Run code on each Stripe Payment, a GitHub Push, or any webhook, without setting up servers.
Multi Tenant Sandbox

Allow your customers to extend your product using Node.js code instead of creating your own DSL.

Webhook Tester allows you to easily test webhooks and other types of HTTP requests.

Huginn is a system for building agents that perform automated tasks for you online. They can read the web, watch for events, and take actions on your behalf. Huginn's Agents create and consume events, propagating them along a directed graph. Think of it as a hackable Yahoo! Pipes plus IFTTT on your own server. You always know who has your data. You do.

RequestBin gives you a URL that will collect requests made to it and let you inspect them in a human-friendly way.
Use RequestBin to see what your HTTP client is sending or to inspect and debug webhook requests.