Learn Swift
Swift is Apple's powerful, modern programming language for iOS, macOS, watchOS and tvOS. It is safe, fast, expressive — and the only language you need to build the next hit app on the App Store.
Swift at a Glance
Clean syntax, powerful type system, and safety built in from the ground up.
import Foundation
let name: String = "Alice"
var score = 95 // Type inferred as Int
// Optional — might have a value or be nil
var nickname: String? = "Ali"
// Safe unwrap with if let
if let nick = nickname {
print("Nickname: \(nick)")
} else {
print("No nickname")
}
print("\(name) scored \(score)")▶ Output
Nickname: Ali Alice scored 95
import Foundation
func greet(person name: String,
from city: String = "Unknown") -> String {
return "Hello, \(name) from \(city)!"
}
// Argument labels make calls read like English
print(greet(person: "Alice", from: "Cape Town"))
print(greet(person: "Bob"))▶ Output
Hello, Alice from Cape Town! Hello, Bob from Unknown!
import Foundation
struct Student {
let name: String
var score: Int
func grade() -> String {
switch score {
case 80...: return "A"
case 70..<80: return "B"
default: return "C"
}
}
}
let alice = Student(name: "Alice", score: 88)
print("\(alice.name): \(alice.grade())")▶ Output
Alice: B
What You'll Learn
Six beginner-friendly modules — from your first Swift program to enums and collections.
Variables & Types
- var and let
- Type inference
- String interpolation
- Type conversion
Optionals
- What is an optional?
- if let unwrapping
- guard let
- Nil coalescing ??
Control Flow
- if / else if / else
- switch with pattern matching
- for-in loops
- while & repeat-while
Functions & Closures
- func keyword
- Argument labels
- Default parameters
- Trailing closures
Structs & Classes
- Structs (value types)
- Classes (reference types)
- Properties & methods
- Initializers
Enums & Collections
- Enumerations
- Associated values
- Arrays & Dictionaries
- Sets
Explore the Mobile category
Swift is the go-to for Apple platforms. For Android and cross-platform apps explore Kotlin, Flutter and React Native alongside Swift.
Frequently Asked Questions
Is Swift only for iOS development?
Swift was created by Apple primarily for iOS, macOS, watchOS and tvOS development. However, Swift is also open source and runs on Linux, and is increasingly used for server-side development with frameworks like Vapor. That said, its primary strength is Apple platform development.
Do I need a Mac to learn Swift?
To build and run iOS apps you need Xcode which requires a Mac. However, you can learn Swift syntax and fundamentals on any platform using online Swift playgrounds, repl.it, or the Swift Playgrounds app on iPad. The examples on this page work without any setup.
What makes Swift different from Objective-C?
Swift is Apple's modern replacement for Objective-C. Swift is much safer (optionals prevent null crashes), has a cleaner syntax, type inference reduces boilerplate, and it compiles faster. New Apple projects use Swift exclusively. Objective-C is only needed for maintaining very old codebases.
What should I learn after Swift basics?
SwiftUI for building modern Apple UIs declaratively, then UIKit for understanding legacy apps. Combine for reactive programming, async/await for modern concurrency, and eventually explore the full Xcode ecosystem for deploying to the App Store.
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The Story of Swift
Real history, real companies, and an honest look at where Swiftshines and where it doesn't — not just a feature list.
Where it came from
Apple released Swift in 2014, led by Chris Lattner, specifically to replace Objective-C — the aging language iOS and macOS development had relied on since the 1980s. Apple designed Swift from scratch to be safer (catching more mistakes at compile time) and considerably faster to write than the Objective-C syntax it replaced.
How it’s actually used today
Swift is the required language for essentially all new iOS, macOS, watchOS and tvOS development — every app in the App Store built in the last several years either uses Swift or is being migrated to it. Apple's own apps (Music, Maps, Health) run on it, and major companies like LinkedIn, Lyft and Airbnb have Swift-first iOS teams.
Strengths & trade-offs
Swift is genuinely safer than Objective-C — its optional-handling system prevents a huge share of the crashes that used to plague iOS apps — but it only really matters if you're building for Apple platforms specifically; it has limited use outside that ecosystem, unlike more general-purpose languages such as Kotlin or JavaScript.
What to learn next
SwiftUI (Apple's modern declarative UI framework) is the near-mandatory next step for anyone building real iOS apps today. Many iOS developers also pick up Kotlin later on if they need to support Android as well.