NOT WORKING (as of Nov 2016): #171

Swift is terribly slow at compiling.

To save yourself the wait, there are great tools that toy around using a power technique: code injection

Prior to Xcode 8, things were easy with plugins.

But with Xcode 8, Apple now has officialy, yet limiting, way to develop for Xcode plugin, and code injection will not work unless Xcode is unsigned.

Code Injection

Code Injection is a plugin to inject code while the app is running.

To use code injection, you have to unsign your Xcode.

Unsign Xcode

MakeXcodePluginsWork, provides a way to unsign (and also to revert to signed) Xcode.

git clone
cd MakeXcodePluginsWork
# Edit makeXcodePluginsWork if you Xcode path is different
# Eg. My Xcode is /Applications/Xcode

There are other tools. All similarly uses steakknife’s unsign.

Build Code Injection Plugin

git clone
open injectionforxcode/InjectionPluginLite/InjectionPlugin.xcodeproj

In Xcode, go to the target and make sure you select your signing team.

Pitfall: In Build Phases > Run Script, it will run codesign with “iPhone Developer”. This might be ambiguous in some cases (at least for me with multiple account). If so, change the script to eg. “iPhone Developer: samwize”.

Build the target.

Restart Xcode.

You should see “Unexpected Code Bundle …”. Load the Bundle.

In Xcode menu, you should see Injection Plugin and Inject Source.

Congrats! You are ready to inject code.

Inject Your Code

Let’s test by adding this special func to a view controller:

func injected() {
    print("I've been injected: \(self)")

This injected func is special as it is the entry point for any code injection. You can write your injected code within.

Run the target.

Then press CTRL = (or Product > Inject Source).

For more usage and limitations (especially for Swift), read the project’s README.


KZPlayground makes use of code injection to create it’s own Playground, for Swift and Objective-C, since it is just code injection.

It also provides control for tweaking stuff so you get a GUI like sliders.




Back to Home