Charles is a Web debugging tool, HTTP monitor, and reverse HTTP proxy for Web developers that includes plain text debugging of HTTPS/SSL. It is built in Java Swing, and runs on all Java platforms. It is an HTTP proxy server that displays requests and responses, complete with HTTP headers. This enables the developer to examine the exact content of HTTP exchanges, including cookies, caching, and redirects. It can also throttle your connection in order to simulate modem conditions. It is a valuable tool for all Web developers and is especially useful for debugging XML RCP, SOAP, Web services, AJAX/XMLHTTP, and Macromedia Flash client-server traffic including AMF, AMF 3, LoadVars, and XML Sockets.
Burp proxy is an interactive HTTP/S proxy server for attacking Web-enabled applications. It operates as a man-in-the-middle between the end browser and the target Web server, and allows the attacker to intercept, inspect, and modify the raw traffic passing in both directions. Text and hex editing may be performed on intercepted traffic. Downstream proxies are supported. Authentication may be done to downstream proxy and Web servers, using basic, NTLM, or digest authentication types.