The best alternatives to RequestBin are Requestly, HTTPDump, and Beew Beta. If these 3 options don't work for you, we've listed a few more alternatives below.
Requestly was built to save developers time by intercepting and modifying HTTP Requests. It has now developed into an open-source alternative to Charles Proxy and Telerik Fiddler that works directly in browsers...
HTTPDump is an app to debug webhook and check the data flowing through your APIs/webhook, You can dump any data on us and check what's going on. One step ahead from requestb.in