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Fiddler Classic

Web Debugging Proxy Tool for Windows

A Windows-only tool that logs HTTP(s) network traffic.

Non-commercial use only | Maintenance mode | Community support | Free

*Please be aware that Fiddler Classic is for non-commercial use only. It is not in active development and offers no commitments for releases, patches or tech support. By using this product, you assume all associated risks. Fiddler Everywhere is the supported tool for professional or commercial use. View the Fiddler Classic End User License Agreement (EULA) here.

Using Fiddler for Work?
Achieve More with Fiddler Everywhere

Fiddler Everywhere is the actively developed and supported Fiddler solution for professional and commercial use. Available on Windows, macOS, and Linux, it builds on Fiddler Classic's trusted debugging foundation with modern protocols, persistent workflows, team collaboration, and AI-assisted development environments.

Modern Protocols

HTTP/2, gRPC, and Server-Sent Events are common in modern architectures. Fiddler Everywhere captures and decodes protocols that Fiddler Classic cannot fully inspect.

Persistent Workflows 

Saved filters, rules and captured snapshots, across recurring debugging workflows, without starting from scratch every time.

Team Collaboration

Share captured sessions, rulesets, and API requests so teammates can review the same traffic-level evidence without screenshots or manual reproduction.

AI-Assisted Debugging

Connect MCP-compatible coding agents such as Claude, Cursor, or Codex to Fiddler so they can inspect sessions, apply filters, and read request and response details.

What Can You Do With Fiddler Classic?

For personal, non-commercial Windows use, Fiddler Classic can help you inspect, compose, mock, and modify HTTP/S traffic.

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Inspector in Fiddler Classic

  • Inspect HTTP/HTTPS Traffic

    Use Fiddler Classic to inspect HTTP/HTTPS traffic to and from browsers and desktop apps. The Traffic Inspector allows you to dive into the details of any specific network request.

  • Create HTTP/S Requests with Composer

    You can access everything you need to create a new request from the API Composer tab. Communicate with the web server with precision, thus calling only the resources you want.

  • Mock or Modify Requests

    Mock services and help with testing behaviors triggered by responses from external providers. Use the AutoResponder to create mock responses and get closer to testing complete.

*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.

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Thousands of Organizations Use Fiddler Everywhere

Join these companies and more than a million developers who are already building, running and debugging
with Fiddler Everywhere.

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4.4

G2.com User Reviews

Fiddler is used by tens of thousands of Users daily and they love it! Don’t just take our word for it. G2 Users have consistently rated Fiddler 4.4 out of 5 stars. G2 is a renowned peer-to-peer review site that aggregates user reviews for business software.

Users of G2.com provide unbiased user reviews after they objectively access business software.

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Next Steps

Choose Fiddler Classic for individual, non-commercial debugging on Windows. Choose Fiddler Everywhere for professional, commercial, team, or cross-platform workflows.

For Non-Commercial Use:

Download Fiddler Classic