Fiddler Orchestra, Fiddler Everywhere and the Future of Fiddler

There seems to be quite some confusion over the latest flavors of Fiddler - Fiddler Orchestra and Fiddler Everywhere. There has been a lack of continuity in announcements on the side of Progress - the current owner of Fiddler. Rather unfortunately, this coincided with staff, management and brand changes that contributed to the confusion.

This post comes to bring all the bits and pieces together and provide a precise state of affairs at the time of writing. It also aims at providing some historical background to give the reader a sense of the direction Fiddler development has been taking and what could be expected further on.

Brief History of Fiddler

Eric Lawrence

Fiddler was created by Eric Lawrence and its initial release was in 2003. Eric was Microsoft's employee at that time (and for quite some time after that) but Fiddler was his personal side project. Microsoft devs, however, used Fiddler a lot and made no secret of it. So, Fiddler was often thought to be a Microsoft product.


In 2012 Telerik - a prominent .NET components vendor acquired Fiddler and Eric Lawrence joined Telerik to work on Fiddler full time.


In 2014 Progress Software acquired Telerik and thus Fiddler became part of Progress' portfolio although still being distributed under the Telerik brand. However, a series of rebrandings happened in the period 2017 - 2018 turning Telerik Fiddler in Telerik by Progress Fiddler, Progress Telerik Fiddler and so on. Eric Lawrence - Fiddler's original creator left Telerik/Progress early 2016.

Author's Relation to Fiddler and the Birth of Fiddler Orchestra

Tsviatko Yovtchev took over Fiddler as lead developer and product manager after Eric Lawrence left Telerik/Progress. In 2017 Tsviatko came up with the idea of making Fiddler distributed and multi-platform and named this new flavor of Fiddler Fiddler Orchestra.

Distributed Fiddler meant Fiddler instances running on different devices being able to share data and control each other. A custom protocol built on top of WebSockets was designed for the task.

Multi-platform Fiddler meant full-fledged Fiddler being able to run on Windows, MAC and Linux under the same UI. In-browser Web UI was chosen for the frontend and Fiddler's engine was rewritten in .NET Core for the backend.

The most detailed presentation on Fiddler Orchestra Vision was made at DevReach 2017.

Fiddler Everywhere - Yet Another Rebranding of Fiddler Orchestra

In 2018 Tsviatko Yovtchev split ways with Progress. At that time the distributed part of Fiddler Orchestra was publicly released and available for download within Fiddler itself. The Web UI was a few weeks short of an initial release including basic functionality.

The new Fiddler management decided to split the distributed and Web UI parts of Fiddler Orchestra while introducing a new name only for the Web UI part and leaving the distributed part under the original name. So the Web UI part was called Fiddler Everywhere and the distributed part remained under the original name Fiddler Orchestra.

To add to the confusion the Fiddler Everywhere was repackaged from ASP.NET Core Web App that runs in the browser to Electron standalone app. What brings even more confusion though is the semi-public release of Fiddler Everywhere. It is publicly available but it is unclear what its relationship to Fiddler and Fiddler Orchestra are. There are also no links to it on the official Fiddler pages at the time of writing.

Flavors of Fiddler and Fiddler Related Products Available at the Time of Writing

Original Fiddler for Windows

This is the original .NET/WinForms Fiddler created by Eric Lawrence back in 2003. It runs only on Windows and in general this is what most developers would mean when referring to Fiddler.

Fiddler Mono Builds

At the original Fiddler for Windows download page there are the "Need Fiddler for OS X too?" and "Need a Linux build?" links that lead to branches of original Fiddler for Windows built for the Mono framework and working on MAC and Linux. While offering the full functionality of the original Fiddler for Windows the Mono builds really suffer from the unstable implementation of WinForms in Mono. Thus they are usable only for simple tasks and limited time.

The team behind Mono has no plans to improve the WinForms support so the development on the Fiddler for Mono is ceased. However, at the time of this writing the downloads are still available and creating some confusion in combination with the multi-platfrom Fiddler Orchestra/Everywhere.

Fiddler Orchestra

This is now a flavor of Fiddler that allows Fiddler instances running on different machines to get data from and control each other. In effect this turns Fiddler into a distributed web debugger. E.g. one can see sessions captured by Fiddler Orchestra instance running on Android phone in the original Fiddler for Windows.

In essence Fiddler Orchestra consists of a .NET Standard port of FiddlerCore (Fiddler's engine) combined with a simple ASP .NET Core MVC Web UI and a feature added to the original Fiddler for Windows. The Web UI is simple enough and does not offer full Fiddler functionality. It only allows setting Fiddler to capture traffic and communicate it to other Fiddler Orchestra instances. In effect one has to run the Fiddler Orchestra feature in the original Fiddler for Windows to be able to analyze the traffic captured.

That being the case Fiddler Orchestra is available for download from within the original Fiddler for Windows since there is not much use of it outside of Fiddler for Windows.

Fiddler Everywhere

An Electron application that aims at duplication all the original Fiddler for Windows functionality thus making Fiddler truly platform agnostic. At the time of writing Fiddler Everywhere includes only a limited subset of the planned functionality.

It is available for download separately from the original Fiddler for Windows and there are no links between the download pages of both products.


This is the engine behind Fiddler for Windows, Fiddler Orchestra and Fiddler Everywhere. It is distributed as .NET and .NET Standard library and it is the only product of the Fiddler line that is not free.

More About the Author

Tsviatko Yovtchev is the creator and long time team lead of JustDecompile, NativeScript and Fiddler Orchestra/Everywhere, JustAssembly diff tool and a number of other developer tools.

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