HTTP Debugger is a professional HTTP sniffer and analyzer for developers.
You can use HTTP Debugger to debug HTTP API calls to a back-end and between back-ends.
HTTP Debugger is very easy of use, with clean UI, and short ramp-up time.
It's not a proxy, and does not produce network issues!
Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
Nessus - Nessus Professional is a security platform designed for businesses who want to protect the security of themselves, their clients, and their customers.
Surge for Mac - Advanced Web Debugging Proxy for Mac & iOS
AlienVault USM (from AT&T Cybersecurity) - AlienVault USM Anywhere delivers powerful threat detection, incident response, and compliance management for cloud, on-premises, and hybrid environments.
HTTP Toolkit - Beautiful, cross-platform & open-source tools to debug, test & build with HTTP(S). One-click setup for browsers, servers, Android, CLI tools, scripts and more.
Tenable.io - Tenable.io Cyber Exposure platform helps to protect any asset on any computing platform and eliminate blind spots.