iOS SDK

import Foil

try FoilClient.shared.configure(
    FoilConfiguration(publishableKey: "pk_live_...")
)

// At action time (signup, login, checkout)
let handoff = try await FoilClient.shared.getSession()

// Package.swift
dependencies: [
    .package(url: "https://github.com/abxy-labs/foil-ios", from: "1.1.0"),
],

import SwiftUI
import Foil

@main
struct MyApp: App {
    init() {
        do {
            try FoilClient.shared.configure(
                FoilConfiguration(publishableKey: "pk_live_your_publishable_key")
            )
        } catch {
            // Reporting only — do not crash on Foil misconfiguration.
            print("Foil failed to configure:", error)
        }
    }

    var body: some Scene {
        WindowGroup { ContentView() }
    }
}

public struct FoilConfiguration: Sendable {
    public static let defaultAPIEndpoint: URL
    public let publishableKey: String
    public var enableBehavioralSignals: Bool
    public var enableHiddenWebView: Bool
    public var enableCloudIdentifier: Bool
    public var enableAutoAttachTouches: Bool
    public var apiEndpoint: URL
}

struct CheckoutView: View {
    func submit() async {
        do {
            let handoff = try await FoilClient.shared.getSession()

            var request = URLRequest(url: URL(string: "https://api.example.com/checkout")!)
            request.httpMethod = "POST"
            request.setValue("application/json", forHTTPHeaderField: "Content-Type")
            request.httpBody = try JSONEncoder().encode(CheckoutRequest(
                items: cart,
                foil: .init(
                    sessionId: handoff.sessionId,
                    sealedToken: handoff.sealedToken
                )
            ))

            _ = try await URLSession.shared.data(for: request)
        } catch {
            // Degrade gracefully — see Error handling below.
        }
    }
}

public struct SessionHandoff: Sendable, Equatable {
    public let sessionId: String
    public let sealedToken: String
}

class CheckoutViewController: UIViewController {
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        FoilClient.shared.observeTouches(on: view, contextId: "checkout")
    }
}

import WebKit

let webView = WKWebView(frame: .zero)
FoilClient.shared.attach(to: webView)
webView.load(URLRequest(url: URL(string: "https://your-app.example.com/signup")!))

let health = await FoilClient.shared.dispatchHealth()
for (channel, stats) in health.channels {
    print(channel,
          "ok:", stats.consecutiveSuccesses,
          "fail:", stats.consecutiveFailures)
}

public struct FoilError: Error, Sendable {
    public enum Code: String, Sendable {
        case invalidPublishableKey = "config.invalid_publishable_key"
        case notConfigured         = "client.not_configured"
        case sessionCreateFailed   = "session.create_failed"
        case batchPostFailed       = "transport.batch_post_failed"
        case handshakeExpired      = "session.handshake_expired"
        case sessionInvalidOrExpired = "session.invalid_or_expired"
        case rateLimited           = "transport.rate_limited"
        case serverUpgradeRequired = "transport.upgrade_required"
        case network               = "transport.network"
        case cryptoFailure         = "crypto.failure"
        case internalError         = "internal"
    }

    public let code: Code
    public let message: String
    public let underlying: Error?
    public let retryable: Bool
}

func foilHandoff() async -> SessionHandoff? {
    do {
        return try await FoilClient.shared.getSession()
    } catch let err as FoilError where err.retryable {
        return try? await FoilClient.shared.getSession()
    } catch {
        reportError(error)
        return nil
    }
}