diff --git a/Sources/SstData/AppSettings.swift b/Sources/SstData/AppSettings.swift
new file mode 100644
index 0000000..9747790
--- /dev/null
+++ b/Sources/SstData/AppSettings.swift
@@ -0,0 +1,45 @@
+import Combine
+import Foundation
+
+/// User preferences, persisted in UserDefaults as soon as a value changes.
+public final class AppSettings: ObservableObject {
+    public static let defaultModelVariant = "large-v3-v20240930_turbo"
+
+    enum Key {
+        static let hotkey = "hotkeyID"
+        static let model = "modelVariant"
+        static let keepHistory = "keepHistory"
+        static let usePriming = "usePriming"
+        static let useCorrection = "useCorrection"
+    }
+
+    private let defaults: UserDefaults
+
+    /// `HotkeyBinding.id` of the key that has to be held.
+    @Published public var hotkeyID: String {
+        didSet { defaults.set(hotkeyID, forKey: Key.hotkey) }
+    }
+    @Published public var modelVariant: String {
+        didSet { defaults.set(modelVariant, forKey: Key.model) }
+    }
+    @Published public var keepHistory: Bool {
+        didSet { defaults.set(keepHistory, forKey: Key.keepHistory) }
+    }
+    /// Give the speech engine the dictionary words as context.
+    @Published public var usePriming: Bool {
+        didSet { defaults.set(usePriming, forKey: Key.usePriming) }
+    }
+    /// Apply the dictionary corrections after transcription.
+    @Published public var useCorrection: Bool {
+        didSet { defaults.set(useCorrection, forKey: Key.useCorrection) }
+    }
+
+    public init(defaults: UserDefaults = .standard) {
+        self.defaults = defaults
+        hotkeyID = defaults.string(forKey: Key.hotkey) ?? "fn"
+        modelVariant = defaults.string(forKey: Key.model) ?? Self.defaultModelVariant
+        keepHistory = defaults.object(forKey: Key.keepHistory) as? Bool ?? true
+        usePriming = defaults.object(forKey: Key.usePriming) as? Bool ?? true
+        useCorrection = defaults.object(forKey: Key.useCorrection) as? Bool ?? true
+    }
+}
diff --git a/Tests/SstDataTests/AppSettingsTests.swift b/Tests/SstDataTests/AppSettingsTests.swift
new file mode 100644
index 0000000..e384f41
--- /dev/null
+++ b/Tests/SstDataTests/AppSettingsTests.swift
@@ -0,0 +1,38 @@
+import Foundation
+import Testing
+@testable import SstData
+
+struct AppSettingsTests {
+    func freshDefaults() -> UserDefaults {
+        let name = "sst-tests-\(UUID().uuidString)"
+        let defaults = UserDefaults(suiteName: name)!
+        defaults.removePersistentDomain(forName: name)
+        return defaults
+    }
+
+    @Test func defaultsMatchTheSpec() {
+        let settings = AppSettings(defaults: freshDefaults())
+        #expect(settings.hotkeyID == "fn")
+        #expect(settings.modelVariant == "large-v3-v20240930_turbo")
+        #expect(settings.keepHistory)
+        #expect(settings.usePriming)
+        #expect(settings.useCorrection)
+    }
+
+    @Test func changesArePersisted() {
+        let defaults = freshDefaults()
+        let settings = AppSettings(defaults: defaults)
+        settings.hotkeyID = "rightOption"
+        settings.modelVariant = "small"
+        settings.keepHistory = false
+        settings.usePriming = false
+        settings.useCorrection = false
+
+        let reloaded = AppSettings(defaults: defaults)
+        #expect(reloaded.hotkeyID == "rightOption")
+        #expect(reloaded.modelVariant == "small")
+        #expect(!reloaded.keepHistory)
+        #expect(!reloaded.usePriming)
+        #expect(!reloaded.useCorrection)
+    }
+}