Using Fiddler to Fix Issues


I’ve helped many users who say Fiddler has “fixed” their issue. Unfortunately, this is a bit deceptive. Fiddler is an excellent debugging tool for web apps, but it does not permanently resolve problems. What it does do is act as a proxy with its own connection settings. This allows it to act as a “man in the middle” and even decrypt the traffic to provide better more insight into application behavior. Sometimes, this is just enough to correct the underlying problem and give the illusion that all is well. This can be very frustrating when trying to find and debug the problem!

I have personally seen Fiddler “help” with the following:

  • Proxy issues
  • TLS versioning
  • SSL cert problems

Telerik themselves have a great post on this here outlining the technical details and corrective actions. If you do any sort of debugging with Fiddler it’s worth a read.

Side Note:

If you help end users, but don’t want them to do a full install, FiddlerCap is a great tool for the job.