Home > REST > Fiddling with Fiddler – debugging REST services on your machine

Fiddling with Fiddler – debugging REST services on your machine


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Fiddler is a “Web debugging proxy” that comes in very handy when you are developing REST services. It logs all http(s) traffic between your machine and internet. It can also log the http(s) traffic on your machine, between e.g. your browser and the web server that you use when you test your REST services. Using this tool you can inspect all http(s) traffic and also build and execute your own requests, based upon a previously made request or from scratch.

When you test your REST service you typically type in the address to your service that runs on your local web server:


Surprise! Fiddler will not log anything! To make Fiddler know about your calls you can do one of two things:

  1. Use the machine name instead of localhost /
  2. Add a dot after the initial part of the address

The following addresses will give you access to your service, but this time Fiddler will log the traffic:


You should of course replace my-machine with the name of your machine. If you still have trouble there is one more trick that can save your day: Disable the IPv6 options under Tools -> Fiddler options

If you haven’t done so already download Fiddler, view the Fiddler quickstart video and start debugging your REST services!

  1. 2010/04/30 at 07:13

    I have a question that how to test the number of page http request in a normal website? It’s need tool?

    • 2010/04/30 at 11:08

      Fiddler is a web debugging tool so if you want to count requests for your website as a part of debugging it Fiddler would be a good choice. If you want to count requests for websites on a server Fiddler would not be the right choice.

  2. Peter
    2012/08/16 at 17:17

    The dot trick doesnt seem to work when using .NET WebRequest’s. The request.GetResponse() doesnt swallow this. using the machinename is the way to go.

    Thanks for the info, i was wondering where all my sub REST calls where going 🙂

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