How to Install, Configure, and Use Fiddler for HTTP/HTTPS Traffic Capture on PC and Mobile

Fiddler is an HTTP debugging proxy tool that can record and inspect all HTTP communications between your computer and the Internet, allowing you to set breakpoints and modify request/response data.

Download the installer (e.g., fiddler4_4.6.2.0_setup.1453708442.exe ) and install it with the default options.

After installation, open Fiddler, go to Tools → Fiddler Options , and in the Connections tab enable the listening port and allow remote connections.

Configure your browser or mobile device to use the PC's IP address and the Fiddler port as a proxy; for browsers set the LAN proxy, and for mobile devices set the manual proxy with the same IP and port.

Common HTTP status codes are listed: 200 (Success), 400 (Bad Request), 404 (Not Found), 500 (Internal Server Error).

Useful shortcuts include Ctrl + X to clear all sessions.

To set breakpoints, use commands in the lower‑left console such as Bpafter www.baidu.com , bpv www.baidu.com , bpu www.baidu.com , bpm www.baidu.com . After a breakpoint is hit, a red “T” appears before the request.

Modify request content by selecting the Raw view in the Inspectors pane, editing the URL or parameters, and then clicking the green Run to Completion button.

Terminate a breakpoint by clicking “Run Complete” in the inspector, entering the Go command, or disabling it in Rules → Auto Breakpoint . Delete a breakpoint by entering bpu (or bpv , bpm , Bpafter ) without additional arguments.

To capture HTTPS traffic from a mobile device, open Tools → Fiddler Options → HTTPS , enable “Capture HTTPS CONNECTs” and “Decrypt HTTPS traffic”, then click OK.

Install the Fiddler root certificate on the phone either by browsing to the proxy address and downloading the certificate (method 1) or by exporting the certificate from Fiddler ( Actions → Export Root Certificate to Desktop ) and transferring it to the phone (method 2). Android users can install the certificate via Settings → Security → Install from SD card; iOS instructions are pending.

To display the server IP in Fiddler, press Ctrl+R or go to Menu → Rules → Customize Rules… , then edit CustomRules.js to add the line FiddlerObject.UI.lvSessions.AddBoundColumn("ServerIP", 120, "X-HostIP"); . Restart Fiddler and the new column will appear, which can be repositioned as needed.

After these steps, Fiddler will be fully configured to monitor and modify HTTP/HTTPS requests from both PC browsers and mobile devices.

Original article by 田军伟, 2017‑02‑22