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Recording

This section covers how to record your test script using both Fiddler and Blazemeter simultaneously. This dual-recording approach gives you the best of both tools.

Why Record from Both?​

ToolWhat it gives you
BlazemeterA .jmx file with all endpoints structured and ready to open in JMeter
FiddlerA detailed view of every request and response - essential for finding where dynamic values come from during correlation

By recording the same session in both tools at the same time, the captured data matches. When you need to correlate a dynamic value (e.g., token, session ID), you can trace it in Fiddler's response and then apply the extraction in JMeter.

Before You Start​

  1. Make sure all tools are set up and configured (see Section 1 - Install Tools)
  2. Know the user flow you are going to record (see Section 2 - Understand Requirements)
  3. Have test credentials and test data ready
  4. Close unnecessary browser tabs and applications to reduce noise

Steps​

1. Start Fiddler​

  • Open Fiddler

  • Disable Capture Traffic (File > Capture Traffic, or press F12) - this prevents Fiddler from capturing all system traffic. Requests coming through the proxy will still be captured

  • Clear any existing traffic (Edit > Remove > All Sessions, or Ctrl+X)

2. Launch Chrome Through Fiddler Proxy​

chrome.exe --proxy-server="http=127.0.0.1:8888;https=127.0.0.1:8888"

Note: If chrome.exe is not in your PATH, use the full path:

"C:\Program Files\Google\Chrome\Application\chrome.exe" --proxy-server="http=127.0.0.1:8888;https=127.0.0.1:8888"

3. Start Blazemeter Recording​

  • Click the Blazemeter extension icon in Chrome
  • Give your test a name (e.g., "Login Flow")
  • Click the record button (red circle)

4. Perform the User Flow​

  • Navigate through the application as a real user would
  • Follow the flow you identified in the requirements
  • Take your time - don't rush. The think times will be replaced later anyway

5. Stop Recording​

  • Click the stop button in Blazemeter (square icon)

  • Fiddler doesn't need to be stopped since Capture Traffic was already disabled - it only captured proxy traffic

6. Export from Blazemeter​

  • Click the .jmx export button in Blazemeter
  • Save the file to your working directory

7. Save Fiddler Session​

  • Save the Fiddler session for reference: File > Save > All Sessions (.saz file)
  • You'll use this during correlation in the next step

Open the Recording in JMeter​

  1. Open JMeter
  2. File > Open > select the .jmx file exported from Blazemeter
  3. You should see all the recorded requests under a Thread Group

At this point, the script is raw - it has all the endpoints but:

  • Names are auto-generated (not meaningful)
  • Dynamic values are hardcoded (needs correlation)
  • No parameterization
  • No assertions or timers

These will be addressed in the next sections.

Tips​

  • Record once, use everywhere - a good recording is the foundation. Take time to do it right

  • Save the Fiddler .saz file - you'll keep going back to it during correlation

  • Don't worry about the messy script - cleanup happens in steps 5 and 6 (correlation and script enhancement)

  • If something goes wrong during recording - just redo it. It's faster to re-record than to fix a bad recording

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