I had a need to debug an external app using fiddler.
Seems to be a trivial exercise, but I could not see the captured traffic in fiddler ?
After Googling a bit, I could only find part of the solution.
Below is the full story.
1. Proxy Settings : First of all you need to know that Fiddler acts as a proxy server on your machine when you start it.
The default address / port is 127.0.0.1:8888
You can check the settings after starting Fiddler in you Browser settings.
So you need to set the proxy settings in your local application that you want to test.
2. Decrypt HTTPS settings
Make sure you have set to Decrypt HTTPS
This needs a extra extension to Fiddler (which is not installed by default)
3. Capture all Processes
After that you need to make sure that you tell Fiddler to capture all traffic for all Processes.
This last step I overlooked for a few hours before my eyes caught the option menu at the bottom.