I work on web development, therefore, in some rare situations I need to test our site and mimic different users' environments such as internet connection. Because if the internet connection is very slow or not stable, un-noticed errors pop up (e.g. one js script loads before the other), ajax request got interrupted, validation request timeout etc.

So for that I want a program to run on Windows 7/8 (7&8 is what I use mainly) to control the speed of the internet (transmission traffic).

Some of the features that I need:


  1. Ability to adjust (limit) internet traffic for downloading.
  2. Adjust traffic for the PC as a whole for all applications
  3. To be free

Recommended but not required:

  1. Adjust traffic (download + upload) for the whole system or for individual applications e.g. affect Firefox only, not Google Chrome.
  2. Monitor traffic with summary of usage (how much data application X used in time N)
  3. To be free (I only need this once every few month, so it's not worth it to buy a full license)

I've tried:

  1. Netlimiter but I couldn't make it work for me.
  2. NetBalancer but the trial has a limited functionality, therefore I couldn't test slowing down connection speed.

Most of the time I do my testing from localhost running XAMPP, so if the tool can control internal server speed that would be a big advantage.

To make this a bit more general and help fellow developers who got the same issue, you may mentioned as well a solution for other environments.

UPDATE [15-11-2014]

I just noticed with the new updates to Google's Chrome Developers tool - under the emulation section an option to emulate mobile device internet speed such as WIFI or 3G. More Details
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  • Can it run in a VM? Commented Feb 19, 2014 at 9:16
  • I guess so, but what will be running on the VM? different OS? And then, would it affect programs outside of VM? Commented Feb 19, 2014 at 9:24
  • Basically you would need to load two VM instances... windows + (linux w/ wanem) Commented Feb 19, 2014 at 9:33
  • Please specify the "brand" of "free": as in "free beer" (no cost), or as in "free speech" (open-source)?
    – Izzy
    Commented Feb 19, 2014 at 9:34
  • @Izzy free beer, not necessarily open source :D I won't mind commercial or freemium as long as it suppresses the speed. Commented Feb 19, 2014 at 10:17

3 Answers 3


[Promoting my comment to an answer...]

WANEM - The Wide Area Network emulator

Controlling Windows bandwidth within Windows is tricky; however, if you build a virtual machine with the Windows webserver in it, then you can do much more with wanem.

In your specific situation, you need:

  • Windows VM with one virtual NIC
  • Linux VM with two virtual NICs, (which would boot the wanem iso)

Jeremy Stretch describes the details of using wanem to control bandwidth / delay on his blog

Other options


I used Fiddler to simulate slow network speeds. At that time, I was using a Windows 7 box. However, at the bottom of the page, they since claim to support a variety of OSs (this covers the "other environments" suggestion).

By default, you have a preset to simulate "modem speeds". However, since Fiddler gives you access "under the hood", you can alter the corresponding scripts to further refine your experience. This tutorial is a good place to start.

Another check-mark on your list is the preference to be free.

I think you can set the speed caps per application, but I cannot recall now this detail, sorry.

As for the other points, I am afraid I wasn't particularly interested in those capabilities when I used it. You might want to check the supported plugins.


Clumsy is a nice portable application that can do network throttling as well as several other network traffic tampering operations.

Clumsy animated gif

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