News on Fiddler Surveys and Telemetry

For this morning’s post, I wanted to give everyone a quick picture of some of the data I've collected about Fiddler usage, how I plan to respond, and how I will continue to learn more.

I’ve recently had the chance to run some surveys and spend some time with developers who are using Fiddler, and it has been an extremely eye-opening process. It became quickly plain that most folks are barely scratching the surface of what they can do with Fiddler, and they often are not using the tool very efficiently.

I plan on improving this in two ways: first, by making tweaks to Fiddler itself to improve its ease-of-use, and secondly, by authoring the first-ever book on Fiddler. It looks like many of you would be interested:

Chart showing 1658 people say they'd pay for a Fiddler book.

… and I’m confident that the book format would allow me to convey information in a more coherent, deeper way than my current series of blog posts, help pages, Wiki’s etc.

I’ve gotten about 35 pages written so far, and I’m presently targeting about 250 pages for the finished product. Currently, the book is organized thusly:

  • Using Fiddler (covers core concepts, UI, major features, major extensions)
  • Extending Fiddler (covers object model, script, building Inspectors, building Extensions)
  • Building on FiddlerCore (covers building applications on the FiddlerCore library)
  • Solving problems with Fiddler (explains, step-by-step, how to accomplish different scenarios with Fiddler).

One interesting challenge in me writing a book on a Fiddler is that it’s allowing me to take a good hard look at every piece of Fiddler as I write about it; I’ve already made dozens of small fixes as I’ve been writing, which is great for Fiddler but bad for my throughput as an author. :-)

In addition to the poll above, I’ve run a few other broad surveys about Fiddler usage. I was surprised to learn that Application and WebService testing is more than twice as popular as Web Site testing, which suggests to me that Web Developers haven’t yet discovered the power that Fiddler provides beyond browser-integrated tools. This is definitely an opportunity to help folks get more out of Fiddler.


Lastly, I’ve run a longer survey about Fiddler which will be up for another week or so to collect deeper information about how Fiddler is getting used.

It looks like most at least 80% of Fiddler users use it every month:


The Fiddler Tutorial videos have tons of information on Fiddler that is hard to find elsewhere; unfortunately, it seems that few folks have seen them:


Much of Fiddler’s power derives from the fact that it’s a web debugging platform, with the ability to enhance it with extensions. Unfortunately, many folks seem to be missing out, although I have noticed that downloads of the Syntax-Highlighting extensions skyrocketed after I put an advertisement for it directly within Fiddler:


Lastly, the survey asked users for information on what I should add to Fiddler next. Rather predictably, most of the proposed features are already available in Fiddler, although some are difficult to find or understand. There were also a number of great suggestions that I’ve been picking off one-by-one over the last month or so; I have a few more to do.

As I’ve gone through this process, it’s become plain that despite Fiddler’s huge user-base (over ten-thousand downloads per day!) I know very very little about how the tool is really getting used in the wild. Fiddler’s telemetry is currently limited to the download count, and the number of Web Service calls for version checking that happen per day (which can be used as a rough approximation of the number of Fiddler sessions).

Microsoft solves this problem with the Customer Experience Improvement Program, a mechanism by which the user can opt-in to providing anonymous data to Microsoft on how products are being used in the wild.

Non-Microsoft tools like Fiddler cannot take advantage of Microsoft’s CEIP service, but I recently encountered RedGate’s SmartAssembly, a very easy-to-integrate toolkit for instrumenting applications with telemetry for feature usage reporting. I’m happy to announce that an upcoming version of Fiddler will introduce the “Fiddler Improvement Program,” enabling you to anonymously send me data about how you’re using Fiddler. This data will help ensure that I’m prioritizing my limited development time effectively. It will also ensure that I understand the mix of system configurations in the wild (e.g. could I move to .NETv4 by default? How many Fiddler users have multiple monitors? How many have displays smaller than 1280x1024? What percentage of Fiddler users have 2gb or less of RAM?)

If you see this prompt, please consider opting in!


Thanks for all the feedback!


Update 8/4/2012: Review some of Fiddler's telemetry data in my new blogpost.