Why Swift in 2026
Swift is the language behind every modern iPhone, iPad, Mac, Apple Watch, and Apple TV app. If you want to ship something to the App Store, Swift is the path. Apple keeps investing in it: SwiftUI (the modern way to build interfaces) gets new features every year, and Swift itself is now open source and runs on the server too. iOS development is also one of the better-paid mobile tracks, partly because Apple users spend more, so businesses pay to reach them. The catch worth knowing before you start: you need a Mac. Xcode, Apple's development tool, only runs on macOS, and there's no real way around that. If you have a Mac, Swift is one of the most rewarding things you can learn, because you can build and run a real app on your own phone within a few weeks.
The Swift vs SwiftUI question
This trips up almost every beginner, so here it is plainly. Swift is the language. SwiftUI is a framework for building user interfaces, written in Swift. You need to know Swift to use SwiftUI. They are not two competing options; one sits on top of the other. So which course first? Start with 100 Days of Swift to get the language foundations, then move to 100 Days of SwiftUI to build real apps. Both courses come from the same teacher and cover overlapping ground, but learning the language before the framework means you understand what your UI code is actually doing instead of copying patterns. Doing both in order is the fastest route to a shippable app. If you only have time for one and you know you want to build apps right now, 100 Days of SwiftUI teaches enough Swift along the way to get going, but you'll be on firmer ground if you do the language course first.
100 Days of Swift: best for language foundations
Paul Hudson's 100 Days of Swift is the most-used free Swift course there is, and for good reason. The format is 100 daily challenges, each one a short bit of reading plus a coding exercise, so you build a steady habit instead of binge-watching a 10-hour video and forgetting it. Over the 100 days you cover Swift syntax, optionals, object-oriented programming, error handling, closures, and protocols: the full language, not just the easy parts. At one hour a day, plan on roughly 3 to 5 months. Honest pros: it's well structured, it's backed by a large community on the Swift forums, and it stays free forever. Honest cons: it leans on UIKit, Apple's older UI framework, rather than SwiftUI, so some of the interface code feels dated; and it doesn't hand you finished Xcode project files, so you do more setup yourself. That setup work is good practice, but know it's there. See the course at /courses/hacking-with-swift-100-days-swift and the platform at /platforms/hacking-with-swift.
100 Days of SwiftUI: best for building real apps
Same teacher, same 100-day structure, but built around SwiftUI, the framework Apple now recommends for new apps. Over the 100 days you learn SwiftUI views, state management, networking, and working with real APIs, and the projects feel like actual apps rather than toy exercises. By the end you've built things you could plausibly put in front of someone. Honest pros: SwiftUI is what Apple steers new developers toward, the projects are genuinely app-shaped, and it's free forever like its sibling. Honest con: it expects some Swift background, so going in cold is harder than it needs to be. That's the case for doing 100 Days of Swift first. See the course at /courses/hacking-with-swift-100-days-swiftui.
What you'll build
These courses are project-heavy, which is the point: you learn iOS by shipping small apps, not by reading about it. Across the SwiftUI curriculum you'll build things like a weather-style app that fetches live data from an API, a custom list app that stores and edits your own data, and a photo-fetching app that works with the device camera and photo library. You'll also build word games, flag-guessing games, and habit trackers along the way. Each one teaches a specific skill (networking, persistence, navigation, state) wrapped in something that actually runs on your phone. By the end you have a small portfolio of working apps, which matters more than any certificate when you're applying for iOS roles.
What to learn next
After both 100-day courses you'll have the language and the framework down. The next steps that pay off: get deeper with Xcode itself (debugging, instruments, the simulator) since fluency there speeds up everything; learn the App Store submission process so you can actually ship; pick up Core Data or SwiftData for storing data on the device properly; and learn how SwiftUI works with Combine for reactive, data-driven UIs. Hacking with Swift has free follow-up articles on most of these. From there it's about building your own apps, because nothing teaches iOS like shipping a real one.
How to choose
If you're new to iOS, do both in order: 100 Days of Swift first for the language, then 100 Days of SwiftUI for building apps. That's the plan the whole guide points to. If you already know a language like Python or JavaScript and just want to get to apps fast, you can start with 100 Days of SwiftUI and pick up the Swift specifics as you go, though you may want to dip back into the language course when something feels unclear. For a full list of free Swift courses in our catalog, see /languages/swift. New to coding entirely and not sure Swift is the right first language? Compare your options in /guides/best-free-coding-courses-2026, or if you're weighing iOS against a data or web path, our /guides/best-free-python-courses-data-science guide lays out the Python side. And if you're choosing between mobile platforms, Android uses Kotlin rather than Swift; our /guides/best-free-kotlin-courses-2026 guide covers the Android side.