I needed to simulate slow network speeds for the iOS simulator. There’s a pretty easy provided way to do it.
Click on Xcode>Open Developer Tool>More Developer Tools…
This will take you to an Apple website to download more tools (or just click here).
Pick “Hardware IO Tools for Xcode” and download it.
The dmg file will have an option for “Network Link Conditioner” – double-click that to install it in your System Preferences.
Now you have a new item in your system prefs…
This will allow you to set your connection speed. It also adds an item to your status bar to quickly turn it off…
