diff --git a/android/app/src/main/java/io/narl/protonstream/settings/SettingsStore.kt b/android/app/src/main/java/io/narl/protonstream/settings/SettingsStore.kt
index b89c439..9794492 100644
--- a/android/app/src/main/java/io/narl/protonstream/settings/SettingsStore.kt
+++ b/android/app/src/main/java/io/narl/protonstream/settings/SettingsStore.kt
@@ -1,6 +1,7 @@
 package io.narl.protonstream.settings
 
 import android.content.Context
+import androidx.core.content.edit
 
 /**
  * The settings that are Android's alone.
@@ -35,6 +36,16 @@ class SettingsStore(context: Context) {
         get() = preferences.getInt(KEY_CACHE_BUDGET_GIB, DEFAULT_CACHE_BUDGET_GIB)
         set(value) { preferences.edit().putInt(KEY_CACHE_BUDGET_GIB, value).apply() }
 
+    /** How the library was last sorted, as a `LibrarySort` name; null for the default. */
+    var librarySort: String?
+        get() = preferences.getString(KEY_LIBRARY_SORT, null)
+        set(value) { preferences.edit { putString(KEY_LIBRARY_SORT, value) } }
+
+    /** Whether the library folds each franchise into one tile. */
+    var libraryGrouped: Boolean
+        get() = preferences.getBoolean(KEY_LIBRARY_GROUPED, true)
+        set(value) { preferences.edit { putBoolean(KEY_LIBRARY_GROUPED, value) } }
+
     companion object {
         /** The desktop's range, in the steps a phone's storage is bought in. */
         val CACHE_BUDGET_CHOICES = listOf(1, 2, 4, 8, 16)
@@ -49,5 +60,7 @@ class SettingsStore(context: Context) {
         private const val KEY_BACKGROUND_AUDIO = "background_audio"
         private const val KEY_HARDWARE_DECODING = "hardware_decoding"
         private const val KEY_CACHE_BUDGET_GIB = "cache_budget_gib"
+        private const val KEY_LIBRARY_SORT = "library_sort"
+        private const val KEY_LIBRARY_GROUPED = "library_grouped"
     }
 }
diff --git a/android/app/src/main/java/io/narl/protonstream/ui/AppViewModel.kt b/android/app/src/main/java/io/narl/protonstream/ui/AppViewModel.kt
index 5a4c4c1..cb0ae37 100644
--- a/android/app/src/main/java/io/narl/protonstream/ui/AppViewModel.kt
+++ b/android/app/src/main/java/io/narl/protonstream/ui/AppViewModel.kt
@@ -25,6 +25,7 @@ import kotlinx.coroutines.flow.callbackFlow
 import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.withContext
 import io.narl.protonstream.native.NativeRuntime
+import io.narl.protonstream.settings.SettingsStore
 import io.narl.protonstream.ui.theme.AppearanceState
 import uniffi.pstr_android.ArrangementRecord
 import uniffi.pstr_android.LibrarySort
@@ -123,7 +124,17 @@ class AppViewModel(context: Context, private val workManager: WorkManager) : Vie
                 it.copy(message = "Certificate verification is unavailable; Proton requests will fail")
             }
         }
-        reload()
+        // The arrangement first, so the first grid is drawn the way the viewer
+        // left it rather than A–Z and then re-sorted under them.
+        viewModelScope.launch {
+            val (sort, grouped) = withContext(Dispatchers.IO) {
+                SettingsStore(appContext).run {
+                    librarySort?.let { name -> LibrarySort.entries.firstOrNull { it.name == name } } to libraryGrouped
+                }
+            }
+            mutableState.update { it.copy(sort = sort ?: it.sort, grouped = grouped) }
+            reload()
+        }
         catchUp()
         viewModelScope.launch {
             val account = runCatching { withContext(Dispatchers.IO) { NativeRuntime.engine().accountState() } }
@@ -153,9 +164,18 @@ class AppViewModel(context: Context, private val workManager: WorkManager) : Vie
     }
 
     /** Reorder the grid, or fold or unfold its franchises. */
+    /** Sort and fold the library, and keep both for the next launch. */
     fun arrange(sort: LibrarySort, grouped: Boolean) {
         mutableState.update { it.copy(sort = sort, grouped = grouped) }
-        viewModelScope.launch { reloadLibrary(mutableState.value.query) }
+        viewModelScope.launch {
+            withContext(Dispatchers.IO) {
+                SettingsStore(appContext).apply {
+                    librarySort = sort.name
+                    libraryGrouped = grouped
+                }
+            }
+            reloadLibrary(mutableState.value.query)
+        }
     }
 
     fun search(query: String) {
diff --git a/ios/ProtonStream/App/AppModel.swift b/ios/ProtonStream/App/AppModel.swift
index 7197257..f0df162 100644
--- a/ios/ProtonStream/App/AppModel.swift
+++ b/ios/ProtonStream/App/AppModel.swift
@@ -44,8 +44,9 @@ final class AppModel {
     /// `grouped`, and the shelves above it. Nil until the bridge has answered,
     /// when the grid falls back to `titles` as they are.
     var arrangement: ArrangementRecord?
-    var sort: LibrarySort = .name
-    var grouped = true
+    /// As the viewer last left them.
+    var sort: LibrarySort = SettingsStore().librarySort
+    var grouped = SettingsStore().libraryGrouped
     var shares: [ShareRecord] = []
     var offline: [OfflineRecord] = []
     var metadataSettings = MetadataSettingsRecord(enabled: false, provider: .aniList, language: "en", ready: true)
@@ -105,6 +106,9 @@ final class AppModel {
     func arrange(_ sort: LibrarySort, _ grouped: Bool) {
         self.sort = sort
         self.grouped = grouped
+        let settings = SettingsStore()
+        settings.librarySort = sort
+        settings.libraryGrouped = grouped
         Task { await reloadLibrary(query) }
     }
 
diff --git a/ios/ProtonStream/App/SettingsStore.swift b/ios/ProtonStream/App/SettingsStore.swift
index 26ca77d..8810147 100644
--- a/ios/ProtonStream/App/SettingsStore.swift
+++ b/ios/ProtonStream/App/SettingsStore.swift
@@ -42,6 +42,23 @@ struct SettingsStore {
 
     static func gibToBytes(_ gib: Int) -> UInt64 { UInt64(gib) * 1024 * 1024 * 1024 }
 
+    /// How the library was last sorted; `.name` until the viewer chooses.
+    var librarySort: LibrarySort {
+        get {
+            let stored = defaults.string(forKey: Key.librarySort)
+            return Self.sorts.first { String(describing: $0) == stored } ?? .name
+        }
+        nonmutating set { defaults.set(String(describing: newValue), forKey: Key.librarySort) }
+    }
+
+    /// Whether the library folds each franchise into one tile.
+    var libraryGrouped: Bool {
+        get { bool(Key.libraryGrouped, default: true) }
+        nonmutating set { defaults.set(newValue, forKey: Key.libraryGrouped) }
+    }
+
+    private static let sorts: [LibrarySort] = [.name, .recent, .added, .release, .rating, .popularity]
+
     private func bool(_ key: String, default value: Bool) -> Bool {
         defaults.object(forKey: key) as? Bool ?? value
     }
@@ -51,5 +68,7 @@ struct SettingsStore {
         static let backgroundAudio = "background_audio"
         static let hardwareDecoding = "hardware_decoding"
         static let cacheBudgetGib = "cache_budget_gib"
+        static let librarySort = "library_sort"
+        static let libraryGrouped = "library_grouped"
     }
 }