How to install Apple’s Network Link Conditioner

Instructions current as of December 8, 2014 – OS X Yosemite 10.10

1. Install Xcode if you don’t have it

2. Open XCode and go to Xcode › Open Developer Tool › More Developer Tools…

   

3. Download Hardware IO Tools for Xcode

1. Open the downloaded disk image and double-click the .prefpane to install it.

   

   

2. There we go!

   

3. Be sure to turn it on. You need to select a profile and enable the network conditioner with the big toggle that should be familiar from the Time Machine prefpane.

   

Caveat

This won't affect localhost, so be sure to use a staging server or co-worker's computer to simulate slow network connections to an API you’re running yourself. You may find https://ngrok.com/helpful in this regard.