Fiddler

Fiddler helps you record, inspect and debug traffic from any web browser. Debug web traffic from any Windows-based PC, Mac or Linux system and mobile devices alike.

Telerik Fiddler Web Debugger is here to help, no matter what platform or language you use to develop. Enjoy!

Which Fiddler Do I Need?

Five Products, One Family, Endless Debugging and Troubleshooting Capabilities.

Fiddler Everywhere
The most powerful web debugging proxy tool for MacOS, Windows and Linux with an enhanced UI. Effectively share your findings and add context with built-in team collaboration. Customize, save, and share rules to handle complicated requests with ease.

Fiddler Classic
The original trusted and secure (free) debugging proxy server tool for Windows. Successfully log, inspect, and alter HTTP(s) network requests and server responses. Go from error to fix in record time. Easily import/export requests in various format and take out the guess work.

Fiddler Jam
A web-based end to end troubleshooting solution for support teams who need to get from error to fix in less time. Capture web traffic, web console logs, and web app screenshots in three simple steps. Easy set-up and requires no programming. Securely share all captured logs within your teams to quickly deliver valuable data for finding a solution.

Fiddler Cap
A Windows only lightweight version of the app designed for data-capture by non-technical users. Capture web traffic and quickly send to your tech team for debugging. Eliminating the annoyances derived from hindered communications. Share network traffic logs within your teams to jump-start the resolution process.

Fiddler Core
Reliable and powerful .NET library allowing you to capture and modify HTTP and HTTPS traffic to ensure everything works smoothly and securely. Harness the power of a stable proxy engine to develop best-in-class features for your .NET solutions and stand out for your ingenuity. Discover delays, missing services and threats in minutes not days.

How to Start Your Fiddler Journey

• Try the Fiddler product(s) that aligns with your needs.
• Integrate Fiddler into your workflow for rapid, elegant debugging and troubleshooting.
• You’ll start realizing the high value of benefits of the app through the acceleration of both your time and cost savings.

Features and Highlights

Web Debugging
Debug traffic from PC, Mac, or Linux systems and mobile devices. Ensure the proper cookies, headers, and cache directives are transferred between the client and the server. Supports any framework, including .NET, Java, Ruby, etc.

Performance Testing
It lets you see the “total page weight,” HTTP caching and compression at a glance. Isolate performance bottlenecks with rules like “Flag any uncompressed responses larger than 25kb.”

HTTP/HTTPS Traffic Recording
The app is a free web debugging proxy which logs all HTTP(s) traffic between your computer and the Internet. Use it to debug traffic from virtually any application that supports a proxy like IE, Chrome, Safari, Firefox, Opera, and more.

Web Session Manipulation
Easily manipulate and edit web sessions. All you need to do is set a breakpoint to pause the processing of the session and permit alteration of the request/response. You can also compose your own HTTP requests to run through the tool.

Security Testing
Use the program for security testing your web applications -- decrypt HTTPS traffic, and display and modify requests using a man-in-the-middle decryption technique. Configure the app to decrypt all traffic or only specific sessions.

Customizing Telerik Fiddler
Benefit from a rich extensibility model, ranging from simple FiddlerScript to powerful Extensions which can be developed using any .NET language.

A Trial of Any of the Fiddler Products Gives You:

• A fully functional version of the software.
• Strict data privacy protection. Your data remains with you, it will never be shared.
• Easy upgrade path to a licensed product.
• Full access to all online documentation, community forums and tutorials.

How to Use

• Launch the application and configure proxy settings
• Capture HTTP/HTTPS traffic from browsers and apps
• Inspect and analyze requests and responses in detail
• Modify requests and responses for testing purposes
• Use filters to focus on specific traffic data
• Debug performance issues with built-in tools
• Decrypt HTTPS traffic for in-depth analysis
• Export session data for reporting and sharing
• Customize Fiddler with extensions and scripting

System Requirements

• Operating System: Windows 7, 8, 10, 11 (64-bit recommended)
• Processor: 1 GHz or faster
• RAM: 2 GB minimum (4 GB recommended)
• Storage: 200 MB available disk space
• Network: Internet connection for updates and features

PROS

• Comprehensive HTTP/HTTPS traffic capture
• Powerful debugging and performance tools
• Customizable with scripts and extensions
• Easy filtering and session analysis
• Supports multiple browsers and applications

CONS

• High CPU usage with large traffic data
• HTTPS decryption requires extra setup
• No built-in automation for repetitive tasks
• Limited support for modern web security protocols

Note: Requires .NET Framework.