Using Fiddler to compare Web Sessions in TeamMentor

After getting the latest version of TeamMentor (TM 3.3 RC3.01), I was experimenting a really annoying behavior. The problem was that the admin credentials provided to login into TM sometimes worked and some times didn’t.

Yeah, I was under the impression that I might be providing wrong credentials, therefore I copied those credentials in a notepad window and I copied and pasted them in the html form fields. Since I was not able to find a pattern for this sporadic situation, I decided to capture the traffic with Fiddler and I tried to compare both Web Sessions, the one that failed and the one that worked.

I discover that Fiddler (with some help from third-party file compare tools like WinMerge), allows to compare both sessions.

So I was able to isolate those sessions :


And using Fiddler’s feature to compare Web Sessions:


And then both sessions are displayed in your default file compare tool, in my case I was using WinMerge.

Using this approach I was at least able to make sure I was using the same credentials and that the error was not related to a wrong credentials.

It did not solve the problem but I realize it’s a really useful tool.

The problem was resolved once I followed Dinis recommendation : removing UserData folder and letting the process to create it again.


About Michael Hidalgo

Michael is a Software Developer Engineer based on San José, Costa Rica. He leads the OWASP Chapter from Costa Rica. You can take a look at my blog at
This entry was posted in Architecture, Tools, UnitTests and tagged , , . Bookmark the permalink.

One Response to Using Fiddler to compare Web Sessions in TeamMentor

  1. Dinis Cruz says:

    You really should be writing scripts for this type of checks/tests

    I would use the O2 Platform REPL scripts to quickly create prototypes and unitests.

    On this topic, can you write a blog post about your current workflow for writing tests? do it in a style like this: (i.e text followed by screenshot)

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