Fiddler

Fiddler is a Web Debugging Proxy which logs all HTTP(S) traffic between your computer and the Internet.

Free Windows

Charles

Charles is an HTTP proxy / HTTP monitor / Reverse Proxy that enables a developer to view all of the HTTP and SSL / HTTPS traffic between their machine and the Internet....

Commercial Mac Windows Linux

Shodan

Shodan is a search engine that lets you find specific computers (routers, servers, etc.) using a variety of filters. Some have also described it as a public port scan...

Freemium Web

Zed Attack Proxy

The Zed Attack Proxy (ZAP) is an easy to use integrated penetration testing tool for finding vulnerabilities in web applications. It is designed to be used by people...

Free Open Source Mac Windows Linux

HttpFox

HttpFox monitors and analyzes all incoming and outgoing HTTP traffic between the browser and the web servers. It aims to bring the functionality known from tools like...

• Discontinued The project is no longer developed. Last version, 0.8.14.1, released in May 2014, is not compatible with Firefox, but the extension still works on XUL-based Firefox forks like https://alternativeto.net/software/waterfox/ and https://alternativeto.net/software/palemoon/

Free Mac Windows Linux Waterfox Pale Moon

HTTP Debugger

HTTP Debugger Pro - A Professional HTTP Sniffer and Analyzer for Developers

Commercial Windows

Graphical HTTP Client

HTTP Client is a Mac OS X Leopard developer tool for debugging HTTP services by graphically creating and inspecting complex HTTP messages.

Commercial Mac

HttpWatch

HttpWatch is an HTTP viewer and debugger that integrates with IE and Firefox to provide seamless HTTP and HTTPS monitoring without leaving the browser window. It's...

Commercial Windows Firefox

apptalk.ninja

App and device communication diagnostics tool for better bug tracking & QA. An easy-to-use tool that monitors http, BLE and iBeacon communication over-the-air...

Freemium iPhone iPad

GraphicalHttpClient

Graphical Http Client is a utility to help you test and interact with REST-based web services. It is lightweight, easy-to-use, and has the following features: - Set...

Commercial $ $ $ Mac

Slowy

Slowy is an OSX app which simulates custom connection's conditions and limits the network traffic. It is created for web developers that work on a local server, to...

Freemium Mac

Andiparos

Andiparos is a fork of the famous Paros Proxy. It is an open source web application security assessment tool that gives penetration testers the ability to spider...

• Discontinued No longer developed, as of 2010: https://code.google.com/archive/p/andiparos/source/default/commits

Free Open Source Mac Windows Linux

RESTed

RESTed allows developers to quickly format and make HTTP requests and view the response. RESTed supports both basic HTTP authentication and OAuth. RESTed shows...

Commercial $ $ $ Mac

Rest Client

Rest Client feature rich rest client for developers to debug and test their RESTful web services. It can be used to request a URL using the following HTTP methods: GET...

Commercial Mac

Uthrottle

Uthrottle is a tool which simulates custom connection’s conditions and limits the network traffic to a specified speed on network interfaces. In complex service...

Commercial Linux