Quickstart: Swift (iOS/macOS)

Build a real-time pub/sub app in 10 minutes.

Prerequisites

• Swift 5.5+
• iOS 15+ / macOS 12+
• RelayX account with API key and secret

Install

Add to your Package.swift:

dependencies: [
    .package(url: "https://github.com/Realtime-Relay/Realtime", from: "1.0.0")
]

Or in Xcode: File → Add Packages → Enter the repository URL.

Basic Example

import Realtime

// Create a message listener
class ChatListener: MessageListener {
    func onMessage(_ msg: NatsMessage) {
        if let data = msg.data as? [String: Any],
           let user = data["user"] as? String,
           let text = data["text"] as? String {
            print("\(user): \(text)")
        }
    }
}

// Initialize client
let client = try Realtime(
    apiKey: "your-api-key",
    secret: "your-secret"
)

client.prepare()

Task {
    try await client.connect()
    
    // Subscribe to messages
    client.on(topic: "chat.room1", listener: ChatListener())
    
    // Publish a message
    try await client.publish(
        topic: "chat.room1",
        message: [
            "user": "swift-user",
            "text": "Hello from Swift!"
        ]
    )
    
    print("Message sent!")
}

SwiftUI Example

import SwiftUI
import Realtime

struct ChatView: View {
    @StateObject private var viewModel = ChatViewModel()
    @State private var messageText = ""

    var body: some View {
        VStack {
            List(viewModel.messages) { message in
                Text("\(message.user): \(message.text)")
            }
            
            HStack {
                TextField("Message", text: $messageText)
                Button("Send") {
                    viewModel.send(messageText)
                    messageText = ""
                }
            }
            .padding()
        }
        .onAppear {
            viewModel.connect()
        }
    }
}

class ChatViewModel: ObservableObject {
    @Published var messages: [ChatMessage] = []
    private var client: Realtime?

    func connect() {
        client = try? Realtime(
            apiKey: "your-api-key",
            secret: "your-secret"
        )
        client?.prepare()
        
        Task {
            try? await client?.connect()
            client?.on(topic: "chat.room1", listener: self)
        }
    }

    func send(_ text: String) {
        Task {
            try? await client?.publish(
                topic: "chat.room1",
                message: ["user": "ios-user", "text": text]
            )
        }
    }
}

extension ChatViewModel: MessageListener {
    func onMessage(_ msg: NatsMessage) {
        if let data = msg.data as? [String: Any],
           let user = data["user"] as? String,
           let text = data["text"] as? String {
            DispatchQueue.main.async {
                self.messages.append(ChatMessage(user: user, text: text))
            }
        }
    }
}

Run It

1. Add your API credentials
2. Run on simulator or device
3. Messages will appear in real-time