diff --git a/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSCore/PlatformServices.swift b/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSCore/PlatformServices.swift
new file mode 100644
index 0000000..f3de052
--- /dev/null
+++ b/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSCore/PlatformServices.swift
@@ -0,0 +1,163 @@
+import Foundation
+import AVFoundation
+
+#if canImport(UIKit)
+import UIKit
+#endif
+
+#if canImport(AppKit)
+import AppKit
+#endif
+
+public protocol ClipboardWriting: Sendable {
+    func write(text: String) async
+}
+
+public struct SystemClipboardWriter: ClipboardWriting {
+    public init() {}
+
+    public func write(text: String) async {
+        #if os(iOS) && canImport(UIKit)
+        await MainActor.run {
+            UIPasteboard.general.string = text
+        }
+        #elseif os(macOS) && canImport(AppKit)
+        await MainActor.run {
+            NSPasteboard.general.clearContents()
+            NSPasteboard.general.setString(text, forType: .string)
+        }
+        #endif
+    }
+}
+
+public actor InMemoryClipboardWriter: ClipboardWriting {
+    public private(set) var lastText: String?
+
+    public init() {}
+
+    public func write(text: String) async {
+        lastText = text
+    }
+
+    public func currentText() async -> String? {
+        lastText
+    }
+}
+
+public struct NotificationPolicy: Sendable {
+    public init() {}
+
+    public func shouldNotify(chat: ChatSummary, message: Message, mentionOnly: Bool) -> Bool {
+        guard !message.isOutgoing, !chat.isMuted else {
+            return false
+        }
+        if mentionOnly {
+            return message.text.contains("@")
+        }
+        return true
+    }
+}
+
+public protocol NotificationScheduling: Sendable {
+    func schedule(chat: ChatSummary, message: Message) async throws
+}
+
+public actor RecordingNotificationScheduler: NotificationScheduling {
+    public private(set) var scheduled: [(ChatSummary, Message)] = []
+
+    public init() {}
+
+    public func schedule(chat: ChatSummary, message: Message) async throws {
+        scheduled.append((chat, message))
+    }
+}
+
+public protocol URLOpening: Sendable {
+    func open(_ url: URL) async
+}
+
+public struct SystemURLOpener: URLOpening {
+    public init() {}
+
+    public func open(_ url: URL) async {
+        #if os(iOS) && canImport(UIKit)
+        await MainActor.run {
+            UIApplication.shared.open(url)
+        }
+        #elseif os(macOS) && canImport(AppKit)
+        await MainActor.run {
+            _ = NSWorkspace.shared.open(url)
+        }
+        #endif
+    }
+}
+
+public struct MediaCache: Sendable {
+    public var root: URL
+
+    public init(root: URL) {
+        self.root = root
+    }
+
+    public func photoPath(fileId: Int32) -> URL {
+        root.appendingPathComponent("photos", isDirectory: true).appendingPathComponent("\(fileId).jpg")
+    }
+
+    public func voicePath(fileId: Int32) -> URL {
+        root.appendingPathComponent("voices", isDirectory: true).appendingPathComponent("\(fileId).ogg")
+    }
+}
+
+public protocol VoicePlayback: Sendable {
+    func load(url: URL) async throws
+    func play() async
+    func pause() async
+    func seek(to seconds: TimeInterval) async
+}
+
+public actor RecordingVoicePlayer: VoicePlayback {
+    public private(set) var loadedURL: URL?
+    public private(set) var isPlaying = false
+    public private(set) var position: TimeInterval = 0
+
+    public init() {}
+
+    public func load(url: URL) async throws {
+        loadedURL = url
+        position = 0
+    }
+
+    public func currentLoadedURL() async -> URL? {
+        loadedURL
+    }
+
+    public func play() async {
+        isPlaying = true
+    }
+
+    public func pause() async {
+        isPlaying = false
+    }
+
+    public func seek(to seconds: TimeInterval) async {
+        position = seconds
+    }
+}
+
+@MainActor
+public final class AccountSwitcherViewModel: ObservableObject {
+    @Published public private(set) var accounts: [Account]
+    @Published public private(set) var activeAccount: Account
+
+    public init(accounts: [Account], activeAccount: Account) {
+        self.accounts = accounts
+        self.activeAccount = activeAccount
+    }
+
+    public func switchToAccount(id: String) {
+        guard let next = accounts.first(where: { $0.id == id }) else {
+            return
+        }
+        activeAccount = next
+    }
+}
diff --git a/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSCore/Storage.swift b/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSCore/Storage.swift
index 76e89e8..150a6de 100644
--- a/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSCore/Storage.swift
+++ b/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSCore/Storage.swift
@@ -13,6 +13,13 @@ public struct AppStoragePaths: Sendable {
             .appendingPathComponent(accountId, isDirectory: true)
             .appendingPathComponent("tdlib", isDirectory: true)
     }
+
+    public func mediaCachePath(for accountId: String) -> URL {
+        root
+            .appendingPathComponent("Accounts", isDirectory: true)
+            .appendingPathComponent(accountId, isDirectory: true)
+            .appendingPathComponent("Media", isDirectory: true)
+    }
 }
 
 public protocol CredentialStore: Sendable {
diff --git a/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSCore/ViewModels.swift b/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSCore/ViewModels.swift
index 03168d9..48344d8 100644
--- a/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSCore/ViewModels.swift
+++ b/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSCore/ViewModels.swift
@@ -264,8 +264,15 @@ public final class ProfileViewModel: ObservableObject {
 public final class MediaViewModel: ObservableObject {
     @Published public private(set) var activePhotoPath: String?
     @Published public private(set) var activeVoicePath: String?
+    @Published public private(set) var isVoicePlaying = false
 
-    public init() {}
+    private let cache: MediaCache?
+    private let voicePlayer: VoicePlayback?
+
+    public init(cache: MediaCache? = nil, voicePlayer: VoicePlayback? = nil) {
+        self.cache = cache
+        self.voicePlayer = voicePlayer
+    }
 
     public func showPhoto(path: String) {
         activePhotoPath = path
@@ -274,4 +281,27 @@ public final class MediaViewModel: ObservableObject {
     public func showVoice(path: String) {
         activeVoicePath = path
     }
+
+    public func cachedPhotoPath(fileId: Int32) -> URL? {
+        cache?.photoPath(fileId: fileId)
+    }
+
+    public func cachedVoicePath(fileId: Int32) -> URL? {
+        cache?.voicePath(fileId: fileId)
+    }
+
+    public func playVoice(url: URL) async {
+        do {
+            try await voicePlayer?.load(url: url)
+            await voicePlayer?.play()
+            isVoicePlaying = true
+        } catch {
+            isVoicePlaying = false
+        }
+    }
+
+    public func pauseVoice() async {
+        await voicePlayer?.pause()
+        isVoicePlaying = false
+    }
 }
diff --git a/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSSmokeTests/main.swift b/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSSmokeTests/main.swift
index 607051b..f8781aa 100644
--- a/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSSmokeTests/main.swift
+++ b/apps/ios/TeleTuiIOS/Sources/TeleTuiIOSSmokeTests/main.swift
@@ -8,6 +8,7 @@ struct TeleTuiIOSSmokeTests {
         try await chatListLoadsDeterministicFakeDataAndFilters()
         try await chatDetailLoadsAndSendsMessage()
         try await messageActionsCoverEditReplyForwardReactDeleteSearchAndCopy()
+        try await platformServicesCoverNotificationsMediaVoiceClipboardAndAccounts()
         try await profileLoadsFromSelectedChat()
         appStorageUsesApplicationSupportStyleAccountPaths()
         print("TeleTuiIOS smoke tests passed")
@@ -100,6 +101,46 @@ struct TeleTuiIOSSmokeTests {
         precondition(!viewModel.messages.contains { $0.id == 1 })
     }
 
+    @MainActor
+    private static func platformServicesCoverNotificationsMediaVoiceClipboardAndAccounts() async throws {
+        let root = URL(fileURLWithPath: "/tmp/TeleTuiIOS")
+        let paths = AppStoragePaths(root: root)
+        let cache = MediaCache(root: paths.mediaCachePath(for: "work"))
+        precondition(cache.photoPath(fileId: 10).path == "/tmp/TeleTuiIOS/Accounts/work/Media/photos/10.jpg")
+        precondition(cache.voicePath(fileId: 20).path == "/tmp/TeleTuiIOS/Accounts/work/Media/voices/20.ogg")
+
+        let policy = NotificationPolicy()
+        let chat = ChatSummary(id: 1, title: "Chat", lastMessage: "hello", isMuted: false)
+        let muted = ChatSummary(id: 2, title: "Muted", lastMessage: "hello", isMuted: true)
+        let incomingMention = Message(id: 1, chatId: 1, senderName: "Alice", text: "@me hello", isOutgoing: false)
+        let incomingPlain = Message(id: 2, chatId: 1, senderName: "Alice", text: "hello", isOutgoing: false)
+        precondition(policy.shouldNotify(chat: chat, message: incomingMention, mentionOnly: true))
+        precondition(!policy.shouldNotify(chat: chat, message: incomingPlain, mentionOnly: true))
+        precondition(!policy.shouldNotify(chat: muted, message: incomingMention, mentionOnly: false))
+
+        let clipboard = InMemoryClipboardWriter()
+        await clipboard.write(text: "copied")
+        let copiedText = await clipboard.currentText()
+        precondition(copiedText == "copied")
+
+        let player = RecordingVoicePlayer()
+        let mediaViewModel = MediaViewModel(cache: cache, voicePlayer: player)
+        let voiceURL = cache.voicePath(fileId: 20)
+        await mediaViewModel.playVoice(url: voiceURL)
+        precondition(mediaViewModel.isVoicePlaying)
+        let loadedURL = await player.currentLoadedURL()
+        precondition(loadedURL == voiceURL)
+        await mediaViewModel.pauseVoice()
+        precondition(!mediaViewModel.isVoicePlaying)
+
+        let personal = Account(id: "personal", displayName: "Personal", databasePath: paths.databasePath(for: "personal"))
+        let work = Account(id: "work", displayName: "Work", databasePath: paths.databasePath(for: "work"))
+        let switcher = AccountSwitcherViewModel(accounts: [personal, work], activeAccount: personal)
+        switcher.switchToAccount(id: "work")
+        precondition(switcher.activeAccount.id == "work")
+        precondition(switcher.activeAccount.databasePath.path.hasSuffix("/Accounts/work/tdlib"))
+    }
+
     @MainActor
     private static func profileLoadsFromSelectedChat() async throws {
         let bridge = FakeSessionBridge(auth: .ready)