Languages & Frameworks

SwiftUI

Build SwiftUI apps with Rivet Actors.

Install

Add the Swift package dependency and import RivetKitSwiftUI:

// Package.swift
dependencies: [
    .package(url: "https://github.com/rivet-dev/rivetkit-swift", from: "2.0.0")
]

targets: [
    .target(
        name: "MyApp",
        dependencies: [
            .product(name: "RivetKitSwiftUI", package: "rivetkit-swift")
        ]
    )
]

RivetKitSwiftUI re-exports RivetKitClient and SwiftUI, so a single import covers both.

Actor Options

The @Actor property wrapper always uses get-or-create semantics and accepts:

name (required)
key as String or [String] (required)
params (optional connection parameters)
createWithInput (optional creation input)
createInRegion (optional creation hint)
enabled (toggle connection lifecycle)

import RivetKitSwiftUI
import SwiftUI

struct ConnParams: Encodable {
    let authToken: String
}

struct ChatView: View {
    @Actor(
        "chatRoom",
        key: ["general"],
        params: ConnParams(authToken: "jwt-token"),
        enabled: true
    ) private var chat

    var body: some View {
        Text("Chat: \(chat.connStatus.rawValue)")
    }
}

Actions

import RivetKitSwiftUI
import SwiftUI

struct CounterView: View {
    @Actor("counter", key: ["my-counter"]) private var counter
    @State private var count = 0
    @State private var name = ""

    var body: some View {
        VStack {
            Text("Count: \(count)")
            Text("Name: \(name)")

            Button("Fetch") {
                Task {
                    count = try await counter.action("getCount")
                    name = try await counter.action("rename", "new-name")
                }
            }

            Button("Increment") {
                counter.send("increment", 1)
            }
        }
    }
}

Subscribing to Events

import RivetKitSwiftUI
import SwiftUI

struct GameView: View {
    @Actor("game", key: ["game-1"]) private var game
    @State private var count = 0
    @State private var isGameOver = false

    var body: some View {
        VStack {
            Text("Count: \(count)")
            if isGameOver {
                Text("Game Over!")
            }
        }
        .onActorEvent(game, "newCount") { (newCount: Int) in
            count = newCount
        }
        .onActorEvent(game, "gameOver") {
            isGameOver = true
        }
    }
}

Async Event Streams

import RivetKitSwiftUI
import SwiftUI

struct ChatView: View {
    @Actor("chatRoom", key: ["general"]) private var chat
    @State private var messages: [String] = []

    var body: some View {
        List(messages, id: \.self) { message in
            Text(message)
        }
        .task {
            for await message in chat.events("message", as: String.self) {
                messages.append(message)
            }
        }
    }
}

Connection Status

import RivetKitSwiftUI
import SwiftUI

struct StatusView: View {
    @Actor("counter", key: ["my-counter"]) private var counter
    @State private var count = 0

    var body: some View {
        VStack {
            Text("Status: \(counter.connStatus.rawValue)")

            if counter.connStatus == .connected {
                Text("Connected!")
                    .foregroundStyle(.green)
            }

            Button("Fetch via Handle") {
                Task {
                    if let handle = counter.handle {
                        count = try await handle.action("getCount", as: Int.self)
                    }
                }
            }
            .disabled(!counter.isConnected)
        }
    }
}

Error Handling

import RivetKitSwiftUI
import SwiftUI

struct UserView: View {
    @Actor("user", key: ["user-123"]) private var user
    @State private var errorMessage: String?
    @State private var username = ""

    var body: some View {
        VStack {
            TextField("Username", text: $username)

            Button("Update Username") {
                Task {
                    do {
                        let _: String = try await user.action("updateUsername", username)
                    } catch let error as ActorError {
                        errorMessage = "\(error.code): \(String(describing: error.metadata))"
                    }
                }
            }

            if let errorMessage {
                Text(errorMessage)
                    .foregroundStyle(.red)
            }
        }
        .onActorError(user) { error in
            errorMessage = "\(error.group).\(error.code): \(error.message)"
        }
    }
}

Concepts

Keys

Keys uniquely identify actor instances. Use compound keys (arrays) for hierarchical addressing:

import RivetKitSwiftUI
import SwiftUI

struct OrgChatView: View {
    @Actor("chatRoom", key: ["org-acme", "general"]) private var room

    var body: some View {
        Text("Room: \(room.connStatus.rawValue)")
    }
}

Don’t build keys with string interpolation like "org:\(userId)" when userId contains user data. Use arrays instead to prevent key injection attacks.

Environment Configuration

Call .rivetKit(endpoint:) or .rivetKit(client:) once at the root of your view tree:

// With endpoint string (recommended for most apps)
@main
struct MyApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
                .rivetKit(endpoint: "https://my-namespace:[email protected]")
        }
    }
}

// With custom client (for advanced configuration)
@main
struct MyApp: App {
    private let client = RivetKitClient(
        config: try! ClientConfig(endpoint: "https://api.rivet.dev", token: "pk_...")
    )

    var body: some Scene {
        WindowGroup {
            ContentView()
                .rivetKit(client: client)
        }
    }
}

When using .rivetKit(endpoint:), the client is created once and cached per endpoint. When using .rivetKit(client:), store the client as a property on App (not inside body) since SwiftUI can call body multiple times.

Environment Variables

ClientConfig reads optional values from environment variables:

RIVET_NAMESPACE - Namespace (can also be in endpoint URL)
RIVET_TOKEN - Authentication token (can also be in endpoint URL)
RIVET_RUNNER - Runner name (defaults to "default")

The endpoint is always required. There is no default endpoint.

Endpoint Format

Endpoints support URL auth syntax:

https://namespace:[email protected]

You can also pass the endpoint without auth and provide RIVET_NAMESPACE and RIVET_TOKEN separately. For serverless deployments, set the endpoint to your app’s /api/rivet URL. See Endpoints for details.

API Reference

Property Wrapper

@Actor(name, key:, params:, createWithInput:, createInRegion:, enabled:) - SwiftUI property wrapper for actor connections

View Modifiers

.rivetKit(endpoint:) - Configure client with an endpoint URL (creates cached client)
.rivetKit(client:) - Configure client with a custom instance
.onActorEvent(actor, event) { ... } - Subscribe to actor events (supports 0–5 typed args)
.onActorError(actor) { error in ... } - Handle actor errors

ActorObservable

actor.action(name, args..., as:) - Async action call
actor.send(name, args...) - Fire-and-forget action
actor.events(name, as:) - AsyncStream of typed events
actor.connStatus - Current connection status
actor.isConnected - Whether connected
actor.handle - Underlying ActorHandle (optional)
actor.connection - Underlying ActorConnection (optional)
actor.error - Most recent error (optional)

Types

ActorConnStatus - Connection status enum (.idle, .connecting, .connected, .disconnected, .disposed)
ActorError - Typed actor errors with group, code, message, metadata