Introduction

Progress® Telerik® Fiddler Classic is a web-debugging tool that monitors, inspects, edits, and logs all HTTPS traffic on Windows. Fiddler Classic is the original product that laid the fondations for the modern-day Fiddler Everywhere application.

Please be aware that Fiddler Classic is not in active development and offers no commitments for releases, patches or tech support. By using this product, you assume all associated risks. We recommend upgrading to Fiddler Everywhere.

Get Started with Fiddler Classic

1. Install Fiddler Classic. You can check more detailed information on how to install Fiddler Classic here.

2. Configure the Fiddler Classic Server. The Fiddler Server is the machine on which Fiddler Classic is installed. Some scenarios may require specific steps for Fiddler Classic to receive and send web traffic. This includes:

   • Types of traffic, like decrypting HTTPS and authenticating with channel-binding tokens
   • Operating systems, like Windows 8, Windows 10, Windows 11 and Mac OSX
   • Network configurations, like monitoring a remote machine, chaining to an upstream proxy, using Fiddler Classic as a Reverse Proxy, monitoring local traffic or monitoring dial-up and VPN connections

3. Configure the Client. The client is the source of the web traffic that Fiddler Classic monitors. Some client applications, operating systems, and devices may require specific steps to send and receive traffic to and from Fiddler. This includes:

   • Browsers, like Firefox, Opera, or IE (when sending traffic to localhost)
   • Applications, like .NET apps, WinHTTP Apps, Java Apps, and PHP/cURL apps
   • Devices, like Android, iOS, Windows Phone 7, and PocketPC devices.

Additional Resources

• Capture traffic with Fiddler Classic
• Capture traffic on macOS, Linux and Windows with Fiddler Everywhere
• Capture and analyze HTTP/2 and TLS1.3 traffic with Fiddler Everywhere
• Capture and analyze HTTPS traffic alongside MCP with Fiddler Everywhere

• Fiddler Homepage