This post notes the steps required in December 2020 to get Fiddler Everywhere to capture traffic coming from an Android phone (on the same network).
Computer: Windows 10, IP: 192.168.1.74
Phone: Nexus 5X (Android 8.1.0), IP: 192.168.1.56
On the computer:
- Install Fiddler Everywhere on the computer
- Enable remote connections in Fiddler
- Go to Settings > Connections > Allow remote computers to connect
- Show Client IP column and set a Contains filter: 192.168.1.56
- Enable HTTPS tracing:
- Go to Settings > HTTPS > Click Trust root certificate
- Press [Yes] in the Windows Security Warning pop-up
- Check the Capture HTTPS traffic checkbox
On the phone:
- Set the phone to use Fiddler as a proxy:
- Go to Wi-Fi > Modify Network > Advanced options > Proxy > Manual
- Proxy hostname: 192.168.1.74
- Proxy port: 8866
- Install the Fiddler CA certificate:
- Use a browser to go to: http://ipv4.fiddler:8866
- Download the certificate
- Enter a certificate name (e.g. Fiddler) and press Save
- Test the setup by visiting https://wikipedia.org
- Confirm the Fiddler certificate is being used (as below)

Reference: https://docs.telerik.com/fiddler-everywhere/get-started/mobile-traffic/configure-android