Fiddler Classic Add-ons

Compressibility

Compressibility is a new Fiddler 4 add-on which allows you to easily find opportunities for compression savings across your entire site. Each resource dropped on the compressibility tab is recompressed using several compression algorithms and formats, and the resulting file sizes are recorded.

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Nitro Cacher

Fiddler add-on to cache API responses based on rules. Useful when working with rate limited APIs or heavy/slow API responses that take up a good amount of time during development.

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Netopsy

Netopsy is an app for viewing network traces (SAZ files) created by the Fiddler web debugging proxy.

• Quickly open an archive and zero in on failed sessions
• View requests and responses in multiple formats to debug issues at various levels of your stack
• Use multiple documents for comparing sessions from multiple users.
• Open large archives with thousands of recorded sessions

Fiddler Client Certificate Select

Client certificates are a commonly used authentication mechanism for server to server calls. Setting up client certificates in Fiddler requires you to export the certificate from the local certificate store. Determining which client certificate is set requires locating the file and inspecting the certificate details. Fiddler Client Certificate Select is a Fiddler extension designed to allow users to select certificates directly from their certificate store for use with Fiddler.

MsgPackViewer

The MsgPackViewer Inspector enables you to to view data in the ​MessagePack format.

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x5s - Automated XSS Security Testing Assistant

x5s aims to assist penetration testers in finding cross-site scripting vulnerabilities. Its main goal is to help you identify the hotspots where XSS might occur by:

• Detecting where safe encodings were not applied to emitted user-inputs
• Detecting where Unicode character transformations might bypass security filters
• Detecting where non-shortest UTF-8 encodings might bypass security filters

neXpert Performance Report Generator

neXpert is a Fiddler add-on which helps identify common web performance issues.

intruder21

Yamagata21 built this extension which allows fuzzing of web applications.

StressStimulus

StressStimulus is add-on which aids in load-testing of web applications.

Smarthost

Smarthost makes it possible to configure Remote IP/Host Remapping independently for each client connected to a single Fiddler instance. Coworkers using the same Wi-Fi proxy can develop pages on the same domain, but point to different hosts on each request. Source code is provided.

MockingBird

MockingBird is a Fiddler extension to transform HTTP requests to another format.

There are lots of reason you might need to debug a HTTP/HTTPs request(s), be it try to recreate a issue and narrow-down the problem in your favorite language editor or compare contents between different request(s) etc. MockingBird is a Progress Telerik FiddlerTM extension to transform a Fiddler's HTTP/HTTPs session to any other format you want e.g. you can generate Java, C#.net or any other language code from selected requests you want to troubleshoot issues for and use the output code in your favourite IDE. It's not limited to just code and can be used to create any format as long as you can create a Mustache template for it e.g. you can create a csv file with selected HTTP request to perform a functional or load test in SOAP UI or JMeter.

Request-To-Code

Chad Sowald's extension converts a captured request into the C# or VB.NET code necessary to issue that request.

WPAD Server

Dave Risney wrote the WPAD Server Fiddler extension, which enables capture of traffic from clients that do not offer explicit proxy settings but do use WPAD (this is an obscure scenario).

Watcher - Passive Security Auditor

Watcher is runtime passive-analysis tool for Web applications. It detects Web-application security issues as well as operational configuration issues.

certInspector

The Certificate Inspector addon enables you to view the server's HTTPS certificate chain and simplifies the task of assigning HPKP directives.

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XML Request Inspector

Fedor Vlasov has written an XML Request viewer that handles x-www-form-urlencoded XML post bodies.

Ammonite - Security Scanner

Ammonite is a web application security scanner extension for Fiddler. Ammonite detects common vulnerabilities such as SQL injection, OS command injection, cross-site scripting, file inclusion, and buffer overflows. Ammonite includes unique features that make it particularly well suited for penetration testers and security professionals.

XML DataSet Inspector

Joris Bijnens has written an XML DataSet Inspector which shows XML data using tabs and grids.

Content Security Policy Generator

Content Security Policy declarations help protect your website from XSS attacks. Generating a CSP that protects your site without breaking things can be tricky, but this Fiddler4 extension makes it easy.

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Per-Response Latency Extension

Oscar Brito's extension enables you to specify latency based on regular expressions or exact URLs. Source code is available.

EAS XML Inspector

The Exchange ActiveSync Inspector for Fiddler provides a human-readable interpretation of the WBXML requests and responses used by Microsoft Outlook and other Exchange clients.

Fast Infoset Inspector

The Fast Infoset Inspector provided by Noemax Technologies allows you to view request and response messages encoded using the Fast Infoset format.
 
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WCF Binary-Encoded Message Inspector

This inspector allows you to view WCF binary-encoded messages in a TreeView.

Microtest Tools Compare

Sometimes developers need to compare different requests from clients and test environments, or between different customers—which can be challenging.

MicroTesting Tools attempt to solve this problem by offering extensions for Fiddler that aid comparisons between requests and responses like XML, POSTS and GET and JSON. Users will be able to find the exact differences and easily visualize them. Testers will be able to find bugs very quickly by just comparing the sessions and finding the differences between the snapshots.