When you are testing a web application, it is very useful to employ a proxy tool to save every request and response. You can manually test every request and analyze the response to find vulnerabilitie

Maskgen is not a recognized web application security testing proxy tool.

Dimitry (Deepmagic Information Gathering Tool) is an information gathering tool, primarily used for reconnaissance, not as an intercepting web proxy for vulnerability testing.

Burp Suite is a well-known integrated platform for performing security testing of web applications, featuring an intercepting proxy that allows testers to capture, inspect, and modify all traffic passing between their browser and the web server. It provides various tools for manual and semi-automated vulnerability discovery, making it ideal for the described scenario.

Proxychains is a tool that forces any TCP connection made by a program to go through a list of proxies, primarily for anonymization or evading firewall rules, not for intercepting and modifying web requests for security testing.