Webhook Tester : Webhook Tester allows you to easily test webhooks and other types of HTTP requests.
patchbay : patchbay.pub is a free web service you can use to implement things like static site hosting, file sharing, cross-platform notifications, webhooks hand...
Requestdiff : Differentiate HTTP headers and content body of two GET URLs.
hyper.rs : Fast and safe HTTP for the Rust language.
httpbin.org : A simple HTTP Request & Response Service.
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.