Debug With Fiddler's AutoResponder

  • Updated

Fiddler is a web debugging proxy server application that captures HTTP and HTTPS traffic and logs it for you to review. Fiddler can also be used to modify ("fiddle with") HTTP traffic for troubleshooting purposes while it's being sent or received.

Fiddler is a useful tool for banner testing because its AutoResponder functionality allows you to test banners from your local device instead of sending a request to a server. It makes the process of developing or testing all types of banners easier, especially those that you can't test on your device, such as local connection banners.


Fiddler is a third-party tool developed and maintained by Telerik and not by Adform.

To start using Fiddler, you need to download and install it on your computer.

To use Fiddler with your Adform Studio banners to auto-respond a file:

  1. In Adform Studio, click the banner that you want to test.

  2. In the toolbar at the top of the page, click Studio_live_preview_icon.png.

    Leave the preview window or tab open until step 12.

  3. Locate and open the downloaded Fiddler application on your computer.

  4. In Fiddler, in the right sidebar, click the AutoResponder tab.

  5. In the right sidebar, select Enable automatic responses.

  6. In Adform Studio, go to your banner's workspace.

  7. In the left sidebar, click file_browser_studio__1_.png.

  8. Click the script that you want to test, for example, script.js.

  9. Drag the script from Adform Studio to the If the request matches... space in Fiddler's right sidebar.

  10. In Fiddler, in the right sidebar, click Save.

  11. In the bottom of the right sidebar, in Rule Editor section, add the same script (script.js) from your local device.

  12. In Adform Studio, refresh the banner preview page that you have opened in step 2. You may need to refresh it a couple of times for Fiddler to read it.

  13. In Fiddler, in the window on the left, the gray line shows that the script from the server has been replaced with your local copy of the file.

By following these steps, you can develop your banners for Adform without having to upload them at all times. Instead, with the help of Fiddler, you can change your code in your local copy of the file and check it by refreshing Adform Studio preview.

You can use Fiddler's AutoResponder functionality for other testing and troubleshooting purposes detailed in Telerik's official documentation.

Was this article helpful?

How we can make it better?

Thank you for your feedback!