Both — the picker lets you choose.

Swift Package Manager?

No network — single-file compile only.

No — this is server-side Swift on Linux, no Apple frameworks.

Swift · online compiler

Run Swift online

Run Swift online — Swift 5 and 6, browser-hosted, no Xcode.

Available versions

Swift 6 Swift 5

Firecracker microVM live per-test verdicts multi-file compile

Swift is Apple's modern language for iOS, macOS, and (increasingly) server-side. Strong types, value semantics, protocols with associated types, and — since Swift 6 — data-race safety by default.

ls-judge runs the Linux Swift toolchain (no Xcode needed) inside a Firecracker microVM.

Starter code

What you get in Swift

Clicking "Run now" opens the playground with this exact code and a matching test case pre-loaded — passes on first Run.

swift

Swift 6

import Foundation
let line = readLine()!
let n = Int(line.trimmingCharacters(in: .whitespaces))!
print(n * 2)

stdin →

expected →

FAQ

Common questions about Swift on ls-judge

Swift 5 or 6?: Both — the picker lets you choose.
Swift Package Manager?: No network — single-file compile only.
UIKit / SwiftUI?: No — this is server-side Swift on Linux, no Apple frameworks.
Free?: Yes.