Creating Mock API Local Server with Swift

📡 Creating Mock API Local Server with Swift

This guide shows you how to quickly spin up a Mock API server using Swift and Swifter, a simple HTTP server engine for Swift.

🛠️ Step 1: Create a Swift Package Project #

In your terminal, run:

swift package init --type executable

This creates a new Swift package with an executable target.

📦 Step 2: Update Package.swift #

Replace the contents of your Package.swift file with the following:

// swift-tools-version:5.7
import PackageDescription

let package = Package(
    name: "MockAPISwift",
    dependencies: [
        .package(url: "https://github.com/httpswift/swifter.git", from: "1.5.0")
    ],
    targets: [
        .executableTarget(
            name: "MockAPISwift",
            dependencies: [
                .product(name: "Swifter", package: "swifter")
            ]
        ),
    ]
)

📂 Step 3: Edit main.swift #

Navigate to Sources/main.swift and replace the contents with:

import Foundation
import Swifter

let server = HttpServer()

server["/home"] = { request in
    let json = """
        [
            { \"id\": 1, \"product\": \"Test1\" },
            { \"id\": 2, \"product\": \"Test2\" }
        ]
    """
    return HttpResponse.ok(.text(json))
}

do {
    try server.start(8082)
    print("Server has started on port 8082. Try to connect now...")
    RunLoop.main.run()
} catch {
    print("Server start error: \(error)")
}

🌐 Example API Endpoint #

After running the server, you can access:

http://localhost:8082/home

It will return a mock JSON response.

🚀 Step 4: Run Your Server #

In the terminal, run:

swift run

🛠 If swift run doesn’t work: #

Try cleaning the project and running again:

swift package clean
swift run

⚠️ Debugging Tips #

• If the server doesn’t respond, try changing the port number in server.start(...)
• Make sure nothing else is using that port (like another local server)
• Check for typos in the JSON string or endpoint path

✅ You’re all set to mock APIs locally with Swift!