Fiddler for Mac Catalina Full Free Download New Version 2022

Fiddler for Mac Catalina Full Free Download New Version 2022

Fiddler for Mac Catalina Download 2022

Fiddler for Mac Beta is now available for download. Try it out today and let us know what you think. Over the years, we have received numerous requests from our user community to provide a Fiddler build for OS X. While Fiddler for Windows can be used as a proxy for apps running on OS X, there is still great value in being able to run Fiddler on OS X natively.

So we have ported the latest version of Fiddler to the Mono Framework which in turn supports OS X—and you can grab the beta bits today.

Download Fiddler for OS X Beta and use our Fiddler forum to leave your comments, ideas and suggestions for further development.

Fiddler allows you to inspect traffic, set breakpoints, and “fiddle” with incoming or outgoing data. Fiddler includes a powerful event-based scripting subsystem, and can be extended using any .NET language.

Fiddler is freeware and can debug traffic from virtually any application that supports a proxy, including Internet Explorer, Google Chrome, Apple Safari, Mozilla Firefox, Opera, and thousands more. You can also debug traffic from popular devices like Windows Phone, iPod/iPad, and others.

fiddler for mac catalina

Web Session Manipulation

Edit web sessions easily:just set a breakpoint to pause the processing of the session and permit alteration of the request/response. Compose your own HTTP requests and run them through Fiddler.

Performance Testing

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

Customizable Free Tool

Benefit from a rich extensibility model, ranging from simple FiddlerScript to powerful extensions which can be developed using any .NET language.
See full list of ready-made add-ons.

Security Testing

Decrypt HTTPS traffic and display and modify web application requests using a man-in-the-middle decryption technique. Configure Fiddler to decrypt all traffic, or only specific sessions.

HTTP/HTTPS Traffic Recording

Use Fiddler to log all HTTP(S) traffic between your computer and the Internet. Debug traffic from virtually any application that supports a proxy (IE, Chrome, Safari, Firefox, Opera and more).

Web Debugging

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

What’s New:

  • Add Packet Capture Import
  • Enhanced Composer
  • Enhanced AutoResponder
  • Improved WebView
  • Enhanced Protocol Violation detection
  • Add registry-fallback to EnableLoopback

Getting Started with Fiddler for OS X Beta

Once you download the new Fiddler for OS X file, follow these steps to get up and running with it:

  1. If you don’t have the Mono framework installed on your Mac, please download it and install it. you already have it installed, please update it to the latest version.
  2. If you just installed Mono, please open Terminal and type in:
    /Library/Frameworks/Mono.framework/Versions/<Mono Version>/bin/mozroots –import –sync 
    The Mono framework has its own trusted root certificates store. Currently (at mono version 4.2.4) this store remains empty after installing Mono on OS X. Fiddler uses the certificates in this store to validate the certificates of the websites visited. So you need to populate this store with a set of commonly trusted root authorities to avoid getting constant certificate warnings by Fiddler. The mozroots tool imports trusted authorities from the Mozilla LXR.
  3. Extract to a folder you have write access to. It is recommended that the full path to the Fiddler install folder does not contain any Windows path illegal characters. (At present it is possible that some Fiddler functionality, e.g. various file exports or Fiddler Script won’t handle such paths.)
  4. Open Terminal and navigate to the folder form 3.
  5. Type mono Fiddler.exe in Terminal.

While the Oct 2016 Fiddler Release for OS X increases development speed, this approach introduced some limitations, which you will find more details about in the next section.

fiddler for mac download

Limitations, Known Problems and Workarounds

Unstable UI

Fiddler for OS X has the same familiar look that Fiddler for Windows has, however, it is built on top of the open source WinForms Mono implementation. The quality of that implementation is significantly lower than that of Microsoft WinForms, and this results in a less than ideal user experience. While we were aware of that when we began our work on the macOS version of Fiddler, we chose to go this way so that we can bring OS X support to life faster, not sacrifice the roadmap for Fiddler for Windows and base our future work on real world usage.

The most problematic areas in the UI for the beta 1 release are resizing the window and resizing elements inside the window. That oftentimes results in poor or laggy redrawing of all the affected elements. Quite often, though, hovering over or clicking on the affected areas will fix things.

When Fiddler is running and ‘decrypt HTTPS traffic’ is on, Safari cannot access some popular sites (Facebook/Twitter/GitHub etc.)

Currently this effect is limited to Safari only and it happens only if you visited the site before opening Fiddler. Cleaning the browsing history (just the history not cache or cookies) for the affected site(s) fixes the problem.

Our preliminary research shows this problem occurs with websites using TLS versions greater than 1.0. The lack of Mono implementation of TLS 1.1 and 1.2 limits Fiddler for macOS to using TLS 1.0 only. Rather unfortunately, Fiddler TLS 1.0 connection comes after TLS 1.2 connection has been made to the same domain which doesn’t seem to be acceptable to Safari.

fiddler for mac install

TLS 1.1 and 1.2 not supported

This is a hard limitation introduced by the current state of TLS implementation in the Mono framework. So Fiddler for OS X cannot use these protocols at present.

SSL/TLS Handshake properties not available

Fiddler for OS X Beta cannot display these at present. This is work in progress.

Auto update

The initial version of Fiddler for OS X can be updated only manually.

Limited lifespan

This version of Fiddler for OS X will work for 60 days and then it will need to be updated. Fiddler is a proxy that aims to debug any problems related to the HTTP traffic between your computer and the Internet. The interface is divided into different tabs where you can access statistics for each website you visit. It also has an ‘inspector’ for viewing the content of each request and corresponding response in different formats.

You can also set filters for unwanted traffic to save time, or take advantage of the time bar, which shows you the transfer for a specific HTTP session. Fiddler is a comprehensive tool that, despite its small size, includes a number of useful features for anyone who has medium to advanced knowledge on the subject.

Configure Fiddler for Mac

Virtualization products like VMWare Fusion or Parallels Desktop permit Fiddler to run in a virtual machine on your Mac.

Configure the Virtual Machine

  1. Install Parallels.
  2. Set the Windows Virtual Machine Hardware > Network 1 Type to Bridged Network mode.
  3. Restart the Virtual Machine.

Configure Fiddler

  1. Install Fiddler on the Virtual Machine.
  2. Open Fiddler.
  3. Click Tools > Fiddler Options > Connections.
  4. Click the checkbox by Allow remote computers to connect.
  5. Restart Fiddler.
  6. Ensure your firewall allows incoming connections to the Fiddler process.
  1. Hover over the Online indicator at the far right of the Fiddler toolbar to display the IP addresses assigned to the virtual machine.
  2. open

    Configure Mac

    the Apple Menu.

  3. Click System Preferences.
  4. ope the Network icon.
  5. Click the Advanced button.
  6. Click the Proxies tab.
  7. Enable the Web Proxy (HTTP) and Secure Web Proxy (HTTPS) options to point to the IPv4 address of the virtual machine using port 8888.

Disable After Use

After using Fiddler, return to the OSX System Preferences and disable the proxy settings.

Proxy Testing a Mac Application with Fiddler

Here we look at using Fiddler as a proxy server in order to test a Mac client application, such as Safari or Visual Studio for Mac, can make web requests through the proxy. Enabling Basic proxy authentication with Fiddler will be covered, as well as using the Fiddler as a proxy without any authentication.

Fiddler will run on a separate Windows machine. Using a separate machine allows us to check that the Mac client application is not bypassing the proxy and making direct web requests to any server. This check can be done by configuring the local firewall to block all direct connections out from the Mac machine but allow connections from the machine running Fiddler.

  • Mac High Sierra 10.13
  • Fiddler 5.0 on Windows

Fiddler Proxy – No authentication

To enable the Mac to use Fiddler as its proxy first configure Fiddler to allow remote connections. This can be done by open the Tools menu, selecting Options, opening the Connections tab, and checking Allow remote computers to connec.

Configuring the Mac to use Fiddler as its proxy server can be done by opening System Preferences – Network. For the active network select the Advanced button and open the Proxies tab. Enter the Fiddler’s machine IP address and port into the Web Proxy (HTTP) and Secure Web Proxy (HTTPS) sections, and ensure both of these are checked.

Finally click OK and Apply to enable the proxy settings.

Now http and https requests should be sent through Fiddler. A simple way to test this is to open Safari and open a web page.

Fiddler Proxy – Basic authentication

To enable Basic proxy authentication in Fiddler open the Rules menu and ensure that Require Proxy Authentication is checked.

This will result in Fiddler requiring Basic authentication with a username ‘1’ and a password ‘1’.

Unfortunately it seems that the native Mac networking API does not work with Fiddler for https requests but will work for non-secure http requests. Opening a web page in Safari will cause the Mac to prompt for the proxy credentials.

Clicking the System Preferences button will show open a dialog where you can enter the credentials for the proxy.

Entering the credentials will result in the Mac’s key chain being updated with the credentials associated with the proxy’s address.

If you open the Mac’s Network settings you will see the Web Proxy and Secure Web Proxy settings now have a username and password associated with them.

Safari will display an error page when accessing a web page over https when the Mac is configured to use Fiddler’s basic authentation proxy.

It seems that for a https request the Mac sends the request with two keep alive headers:

  • Connection: keep-alive
  • Proxy-Connection: keep-alive

Fiddler responds with a 407 proxy authentication required response and a close header.

  • Connection: close

Since the keep-alive is not being honoured by Fiddler the web request sent from the Mac fails and an kCFErrorDomainCFNetwork 310 error occurs. This maps to the kCFErrorHTTPSProxyConnectionFailure status code.

Other applications that do not use the native Mac networking API, such as the Google Chrome web browser, will work with Fiddler and will prompt for credentials.

Unfortunately you currently cannot use Fiddler with basic proxy authentication enabled to test a Mac application making https requests. As an alternative you can use another proxy server, such as Apache.