Click Free download.

1. Select Client application development/debugging in the drop-down menu.
2. Enter your email address, for example, [email protected] in Your Email field.
3. Select the I accept the Fiddler End User License Agreement check box.
4. Click Download for Windows.

Click FiddlerSetup.exe to run the Fiddler installer.

Click I Agree.

Click Install.

Click Close.

1. Click the Windows logo to launch the Start Menu.
2. Search for fiddler.
3. Click Fiddler 4.

Click Cancel.

Click WinConfig.

Click No.

1. Click Exempt All.
2. Click Save Changes.
3. Click the X to close the AppContainer Loopback Exemption Utility pop-up window.

Note: If you do not want to Exempt All, you can accept  Work or school account, or any of the immersive apps you want to capture traffic for. This setting captures UWP application traffic and setting on Windows 10. By default, Fiddler captures traffic only for Win32 app types.

1. Select Tools.
2. Select Options...

Select the Decrypt HTTPS traffic check box.

Click Yes.

Click Yes.

Click Yes.

Click OK.

Click X.

To toggle Capture Traffic on and off, you can either press F12 or select File > Capture Traffic.

After initial installation, Fiddler starts capturing by default. Note the Capturing message in the bottom left corner.

To toggle Capture Traffic on and off, you can either press F12 or select File > Capture Traffic.

1. Select the first item in the list, where Host is www.fiddler2.com.
2. Click Inspectors. 
3. Select Raw or the most suitable view for your troubleshooting. Because most MDM communication is in SyncML format, for Windows 10, always select XML.
4. Click Response body is encoded. Click to decode.
5. Select Raw.

The upper window shows what is sent from the device to the endpoint, and the lower window shows the response from the server to the device. When Fiddler is first launched, it attempts to check for updates and sends its current version. The server then replies with the latest version of Fiddler and the release notes for the latest releases. This is a simple example to show the type of information we can retrieve, but for our troubleshooting, we can use this method and tool to debug enrollment issues and push profiles, for example.

When troubleshooting Windows 10, you can filter out all the noise other than your device services server, by adding a filter:

1. Select the Filters tab.
2. Select the Use Filters check box.
3. Select Show only the following Hosts.
4. Enter your host name, for example, hol.awmdm.com.
5. Select Actions > Run Filterset now.

Note: You can also quickly filter and apply other helpful actions by right-clicking one of the traffic elements in the left pane. You can get advanced and replay requests and even modify data before replaying the request to see if it changes the response.