Learning to develop Apple apps for iOS devices and Macs can be incredibly lucrative. TechRepublic sister site CNET reported that developers building Apple apps bring in 64% more earnings than their Android developer counterparts.

If you want to try to squeeze more cash from your development time, these free PDF downloads from TechRepublic will help developers of any skill level learn the basics about building apps for Apple devices.

Cheat sheet: How to become an iOS developer

The world is going mobile, and so are a lot of companies that rely on apps to reach consumers or perform work. That means iOS developers are a hot commodity who can earn a lot in the right position. This guide on becoming an iOS developer will help those interested in a mobile development career learn what iOS developers do, how they do it, and the skills needed to become an in-demand Apple developer.

Cheat sheet: Apple's Swift programming language

Apple apps and operating systems were long built on a language called Objective-C, which is essentially the C programming language with added object-oriented features. Apple has since replaced Objective-C with its own programming language called Swift, which delivers far superior on-device performance: 2.6x faster than Objective-C and 8.4x faster than Python, in fact. This cheat sheet to Apple’s Swift programming language will help developers learn what’s special about Swift and how it can be used to build iPhone, iPad, and Mac apps.

The Apple Developer Program: An insider's guide

The Apple Developer Program gives subscribers access to all the tools needed to build apps for iOS, watchOS, and macOS. Tools that come with a paid developer account include access to public app beta testing through the TestFlight app, development support from Apple employees, access to all of Apple’s app extensions, permission to publish apps on the app store, and more. The Apple Developer Program has two enterprise level options: The Apple Developer Enterprise Program and the MFi hardware certification program.

Cheat sheet: Apple's ARKit

Augmented reality (AR) is poised to be one of the next big things in tech; Apple developers looking for a particular skill to learn would do well to familiarize themselves with Apple’s ARKit. ARKit is Apple’s augmented reality framework built for iOS apps. It’s also tightly integrated with Apple hardware and is able to take advantage of the advanced spatial mapping technology of the newest iPhone cameras. This cheat sheet will help developers become familiar with Apple’s ARKit, its capabilities, and how to use it.

Cheat sheet: AR Tools from Apple: RealityKit and Reality Composer

If ARKit is the basic framework needed to use AR on iOS devices, then RealityKit and Reality Composer are the tools that allow small-scale developers to build AR experiences that rival those typically reserved for large companies with deep pockets. RealityKit makes AR objects photorealistic, adds physics effects, and allows AR objects to display effects. Reality Composer is an AR prototyping platform that provides a library of pregenerated objects and lets AR developers easily add animations and other effects to their AR elements. This cheat sheet will familiarize developers with the ins and outs of these two augmented reality tools for Apple’s iOS.