How to use Charles Proxy on the Xcode 6 (iOS 8) Simulator?

Update: Charles 3.9.3+ has a built-in function to configure your iOS Simulators (i.e. installing the Charles SSL Certificate). This can be found in the Help menu within the Charles application. (Help > SSL Proxying > Install Charles Root Certificate in iOS Simulators)

The following applies to Charles 3.9.2:

Download the configuration shell script from the Charles Proxy website. Then, replace the script with the following, and run it on your Mac:

#/bin/bashinstall() {if [ -f "$SQLITEDBPATH" ]; thencp -n "$SQLITEDBPATH" "$SQLITEDBPATH.charlesbackup"sqlite3 "$SQLITEDBPATH" <<EOFINSERT INTO "tsettings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fi}for SQLITEDBPATH in ~/Library/Developer/CoreSimulator/Devices/*/data/Library/Keychains/TrustStore.sqlite3; do    echo $SQLITEDBPATH    installdoneecho "The Charles SSL CA Certificate has been installed for the iPhone Simulator"

Some things to note:

• you must open Charles before launching the simulator. If you close Charles, network requests will fail until you restart the simulator
• you will need to do this every time you "Reset Content and Settings..." on the simulator
• For Xcode 5: if you're looking to setup Charles Proxy on Xcode 5 and earlier, you don't need to modify the original script. Just download it from the Charles website and run it as-is

I just tested Charles over Xcode 7 / iOS9 simulator. Just a few pointers I want to add if you're having trouble:

• Make sure "Enable Mac OS proxy" and "Use HTTP Proxy" are checked underCharles' Proxy | Proxy Settings; and optionally check "Enable Mac OS Xproxy at startup" if you don't want to do this step every time youstart Charles.
• If your Automatic Proxy Configuration (and/or Auto Proxy Discovery) is set in your SystemPreferences | Network, you need to uncheck it lest Charles' WebProxy (HTTP) and Secure Web Proxy (HTTPS) will not take effect.
• If your company requires proxy server independent of Charles, youneed to manually replicate the settings inside Charles lest they are overridden by Charles and you won't be able to access the internet. Make note of the proxyURL and port numbers before starting Charles. Transcribe these WebProxy and Secure Web Proxy settings under Charles' Proxy | ExternalProxy Settings.
• "Enable SSL Proxying" and add your endpoint on the list, via Charles'Proxy | SSL Proxying Settings.
• "Install Charles Root Certificate in iOS Simulator" via Charles' Help| SSL Proxying menu.
• And yeah, make sure Charles is setup and started first before youstart the simulator.
• Finally for now, disable ATS during development until we hear morefrom Apple.

According to charles documentation

The iOS Simulator should use the system proxy settings. If it doesn't, please try quitting and restarting the iOS Simulator. As of Xcode 6 it appears to be important that Charles is running and set as the Mac OS X system proxy before you run the iOS Simulator.

Read Here

So just quit your simulator, open charles and then run the app again. After that you can track your network calls.

NOTE: Your network calls will fail if you quit Charles. So you will need to either quit the simulator and run it again or open Charles again.