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In our last some post with our JMeter Series, we saw introduction of JMeter and its related components. This topic is kind of off topic in JMeter series, but still we need this to understand before moving forward. We already know what Fiddler is, if you are new to it, please go through details here real quick to get an insight on Fiddler. As you know in JMeter we will mostly work with HTTP request (Web Applications), we might sometimes need an advanced option to debug our HTTP request and response. Within JMeter we already have Request and Response tabs, but still Fiddler can be more handy (Since its built for that purpose). In order for us to link JMeter with Fiddler we need to do following steps

Step 1

First we need to know which port Fiddler is listening to grab the request and response. This you can naviagate in Fiddler to Tools à Fiddler Options à Connections Tab as shown below

As you can see above, currently Fiddler is listening on port number 8888

Step 2

Now we need to run our JMeter on port number 8888 , which we can do via command line option as shown below

All we are saying here to JMeter is to run on port number (-P) 8888. Now while running tests in JMeter, we can see actual request and response in the Fiddler window as shown below

In all our upcoming discussions, we will work with JMeter along with Fiddler. Please leave your comments and Thanks for reading !!! Thanks, Karthik KK

Post Author: Karthik kk

7 Replies to “JMeter with Fiddler (Series)”

  1. Hi KarthiK,

    Thanks for sharing this post. Its interesting to know Jmeter working with Fiddler .

    Can you post more on posts on Fiddler with Jmeter.


  2. Hi, Thanks for your post,

    I tried the same but after executing my JMeter Script, i am getting an error as –
    Non HTTP response message: Connection to http://IPADDRESS:8888 refused

    Can you suggest any fix?

  3. 1. Can i do it with GUI Mode also.
    2. What about launching fiddler shows alert message port 888 is already in use will you allow fiddler to run on another port.
    3. I tried all steps, but still nothing is getting displayed in fiddler.
    4. IEInspector HTTP Analyzer is good to capture all dynamic requests with jmeter, but unfortunately its a paid tool with 15 days trial only.

  4. Hi Karthik,

    My application is developed using Agular JS (Front End) and .Net (Backend programming) using MVC framework. Does Jmeter support anugular JS apps for performance testing.


    1. Ofcourse yet, since JMeter only looks for the POST/GET HTTP response protocols, not the UI technology I guess.

      Karthik KK

  5. Hi Karthik,

    On Azure VM i have installed fiddler and apache jmeter
    Fiddler installer versionv 5.0.20182.28034 for .NET 4.6.1
    Jmeter Version 5.1;

    I am getting error
    An error occurred: null
    Press any key to continue . . .

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