Web proxies are specialized tools that can be set up between a browser/mobile application and a back-end server to capture and view all the web requests being sent between both ends, essentially acting as man-in-the-middle (MITM) tools. While other Network Sniffing applications, like Wireshark, operate by analyzing all local traffic to see what is passing through a network, Web Proxies mainly work with web ports such as, but not limited to, HTTP/80 and HTTPS/443.
OWASP Zed Attack Proxy (ZAP) is another common web proxy tool for web penetration testing. ZAP is a free and open-source project initiated by the Open Web Application Security Project (OWASP) and maintained by the community, so it has no paid-only features as Burp does. It has grown significantly over the past few years and is quickly gaining market recognition as the leading open-source web proxy tool.