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Run Swift Online

Write, run, and debug Swift code online using a command-line Swift environment. Manage multiple files, save your workspace, and share code without installing Xcode.

Pre-installed Libs
🚀 16,695 total executions (356 this month)

Udemy Logo Udemy Affiliates: The best Swift courses you should try

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🍎 About This Swift Online Executor

The CodeUtility Swift Executor lets you write and run Swift code directly in your browser - no Xcode, SDK, or macOS setup required. It runs real Swift compilers in isolated sandboxes to deliver accurate, native Swift behavior.

This tool supports multiple Swift versions - 5.7, 5.9, and the latest release - giving you the flexibility to explore new language features and maintain compatibility with older Swift codebases.

It’s perfect for developers learning Swift syntax, testing algorithms, or experimenting with code for iOS, macOS, and server-side Swift without needing to install local tools or simulators.

Each snippet runs securely in a containerized Swift environment, ensuring real compiler feedback and safe code execution.

More than a code runner

Use a multi-file editor, an isolated execution terminal, runtime-specific libraries, persistent workspaces, sharing, and real-time collaboration from the same executor.

How to use this executor?

Choose a runtime, open or create a file, write your code, and select Run. Output appears in the terminal, while signed-in users can keep files in a workspace, install libraries, and collaborate through shares.

  1. Select a version and edit the current file or open another workspace file.
  2. Run the code, provide input in the terminal when requested, and review saved run history.
  3. Use libraries, workspace tools, sharing, and chat when your task needs more than one snippet.

💡 Swift Basics Guide for Beginners

1. Declaring Variables and Constants

Use var for variables and let for constants in Swift.

var age = 30
let pi = 3.14159
var name = "Alice"
let isActive = true

// Constants cannot be reassigned
// pi = 3.14 // ❌ Error

2. Conditionals (if / switch)

Use if, else if, else for logic, and switch for multiple branches.

let number = 2
if number == 1 {
    print("One")
} else if number == 2 {
    print("Two")
} else {
    print("Other")
}

switch number {
case 1:
    print("One")
case 2:
    print("Two")
default:
    print("Other")
}

3. Loops

Swift supports for-in, while, and repeat-while loops.

for i in 0..<3 {
    print(i)
}

var n = 3
while n > 0 {
    print(n)
    n -= 1
}

4. Arrays

Arrays store ordered collections of values.

var numbers = [10, 20, 30]
print(numbers[1])

5. Array Manipulation

Use array methods like append and removeLast.

var nums = [1, 2, 3]
nums.append(4)
nums.removeLast()

for n in nums {
    print(n)
}

6. Console Input/Output

Use print() for output. Input requires additional work in Swift Playgrounds or Xcode.

let name = "Alice"
print("Hello, \(name)")

7. Functions

Define reusable functions with parameters and return values.

func add(a: Int, b: Int) -> Int {
    return a + b
}

print(add(a: 3, b: 4))

8. Dictionaries

Dictionaries store key-value pairs.

var ages = ["Alice": 30]
print(ages["Alice"] ?? 0)

9. Error Handling

Swift uses do-catch for error handling.

enum MyError: Error {
    case runtimeError(String)
}

do {
    throw MyError.runtimeError("Something went wrong")
} catch let error {
    print(error)
}

10. File I/O

Swift uses FileManager or String methods for file I/O.

let text = "Hello File"
try text.write(toFile: "file.txt", atomically: true, encoding: .utf8)
let content = try String(contentsOfFile: "file.txt")
print(content)

11. String Manipulation

Use methods like count, contains, uppercased(), etc.

let text = "Hello World"
print(text.count)
print(text.contains("World"))
print(text.uppercased())

12. Classes & Objects

Swift supports OOP using class and init.

class Person {
    var name: String
    init(name: String) {
        self.name = name
    }
    func greet() {
        print("Hi, I'm \(name)")
    }
}

let p = Person(name: "Alice")
p.greet()

13. Optionals

Swift uses ? and ! to handle optional values.

var name: String? = "Alice"
print(name ?? "Unknown")

if let unwrappedName = name {
    print(unwrappedName)
}