Fiddler is a desktop proxy program that can not only log all HTTP(S) traffic between your computer and the Internet but also capture network traffic between mobile devices (iOS and Android) and the internet. In order to use Fiddler to record and inspect network traffic for a mobile phone, you have to firstly enable remote connections in Fiddler on your computer, then connect your mobile phones to the proxy server on your computer. Check out details below.
Allow connections from other devices in Fiddler
Run Fiddler on your PC or Mac. We will use its Windows version in Windows 10 in this demo. Go to the Tools menu, choose Options. A new dialog pops up. Click to access the Connections tab in Options. Select the Allow remote computers to connect checkbox to enable it. You will get the Enabling Remote Access warning saying this options allows remote clients to bounce traffic through your PC’s network connection and you have to restart the proxy server for this change to take effect. Click OK button to confirm. Restart Fiddler. Then following below steps to setup your Android phone to connect to the proxy server on your PC.
Connect Android Device to proxy server
Connect your mobile phone to the same Wi-fi network as your desktop computer. Your PC and Android device should be discoverable on the same network. Open Settings on your phone, tap Wi-Fi, touch and hold on your current WiFi network until you see a pop-up menu. Choose Modify network. Check Show advanced options, select Manual, type your computer’s IP address in the Proxy host name field, type 8888 in the Proxy port field, then save the HTTP proxy settings and quit.
Go to open your mobile browser and visit any website, you should see your device’s traffic in Fiddler on the laptop or desktop.
Capture HTTPS Traffic from Android phone
Fiddler is able to capture all HTTP network traffic from your mobile phone now. But those SSL protected network traffic is invisible in Fiddler on your computer. To record and inspect HTTPS traffic on the mobile, you have to install the Fiddler Root certificate on your Android phone or tablet.
Open Chrome or any other web browser on your Android, visit http://ipv4.fiddler:8888. You will see the Fiddler Echo Service page with a link at the bottom to download Fiddler Root certificate. Tap to download the Fiddler root certificate to your mobile phone. Once it has been downloaded, tap on the .cer file to open it and follow on-screen tips to install the certificate on your device.
After that you should be able to capture HTTPS traffic from/to your Android phone as well.