diff --git a/app/lib/controller/collections_controller.dart b/app/lib/controller/collections_controller.dart
index 7ec448fa..5777d4a5 100644
--- a/app/lib/controller/collections_controller.dart
+++ b/app/lib/controller/collections_controller.dart
@@ -8,16 +8,22 @@ import 'package:nc_photos/account.dart';
 import 'package:nc_photos/controller/collection_items_controller.dart';
 import 'package:nc_photos/di_container.dart';
 import 'package:nc_photos/entity/collection.dart';
+import 'package:nc_photos/entity/collection/util.dart';
 import 'package:nc_photos/entity/collection_item.dart';
 import 'package:nc_photos/entity/collection_item/util.dart';
 import 'package:nc_photos/entity/file_descriptor.dart';
+import 'package:nc_photos/entity/sharee.dart';
+import 'package:nc_photos/exception.dart';
 import 'package:nc_photos/or_null.dart';
 import 'package:nc_photos/rx_extension.dart';
 import 'package:nc_photos/use_case/collection/create_collection.dart';
 import 'package:nc_photos/use_case/collection/edit_collection.dart';
 import 'package:nc_photos/use_case/collection/list_collection.dart';
 import 'package:nc_photos/use_case/collection/remove_collections.dart';
+import 'package:nc_photos/use_case/collection/share_collection.dart';
+import 'package:nc_photos/use_case/collection/unshare_collection.dart';
 import 'package:np_codegen/np_codegen.dart';
+import 'package:np_common/ci_string.dart';
 import 'package:np_common/type.dart';
 import 'package:rxdart/rxdart.dart';
 
@@ -183,6 +189,54 @@ class CollectionsController {
     }
   }
 
+  Future<void> share(Collection collection, Sharee sharee) async {
+    try {
+      Collection? newCollection;
+      final result = await _mutex.protect(() async {
+        return await ShareCollection(_c)(
+          account,
+          collection,
+          sharee,
+          onCollectionUpdated: (c) {
+            newCollection = c;
+          },
+        );
+      });
+      if (newCollection != null) {
+        _updateCollection(newCollection!);
+      }
+      if (result == CollectionShareResult.partial) {
+        _dataStreamController.addError(const CollectionPartialShareException());
+      }
+    } catch (e, stackTrace) {
+      _dataStreamController.addError(e, stackTrace);
+    }
+  }
+
+  Future<void> unshare(Collection collection, CiString userId) async {
+    try {
+      Collection? newCollection;
+      final result = await _mutex.protect(() async {
+        return await UnshareCollection(_c)(
+          account,
+          collection,
+          userId,
+          onCollectionUpdated: (c) {
+            newCollection = c;
+          },
+        );
+      });
+      if (newCollection != null) {
+        _updateCollection(newCollection!);
+      }
+      if (result == CollectionShareResult.partial) {
+        _dataStreamController.addError(const CollectionPartialShareException());
+      }
+    } catch (e, stackTrace) {
+      _dataStreamController.addError(e, stackTrace);
+    }
+  }
+
   Future<void> _load() async {
     var lastData = const CollectionStreamEvent(
       data: [],
diff --git a/app/lib/entity/collection.dart b/app/lib/entity/collection.dart
index a9bdca0f..858860d3 100644
--- a/app/lib/entity/collection.dart
+++ b/app/lib/entity/collection.dart
@@ -1,5 +1,6 @@
 import 'package:copy_with/copy_with.dart';
 import 'package:equatable/equatable.dart';
+import 'package:nc_photos/entity/collection/util.dart';
 import 'package:nc_photos/entity/collection_item/sorter.dart';
 import 'package:nc_photos/entity/collection_item/util.dart';
 import 'package:to_string/to_string.dart';
@@ -40,6 +41,9 @@ class Collection with EquatableMixin {
   /// See [CollectionContentProvider.itemSort]
   CollectionItemSort get itemSort => contentProvider.itemSort;
 
+  /// See [CollectionContentProvider.sharees]
+  List<CollectionShare> get shares => contentProvider.shares;
+
   /// See [CollectionContentProvider.getCoverUrl]
   String? getCoverUrl(
     int width,
@@ -77,6 +81,8 @@ enum CollectionCapability {
   labelItem,
   // set the cover image
   manualCover,
+  // share the collection with other user on the same server
+  share,
 }
 
 /// Provide the actual content of a collection
@@ -106,6 +112,10 @@ abstract class CollectionContentProvider with EquatableMixin {
   /// Return the sort type
   CollectionItemSort get itemSort;
 
+  /// Return list of users who have access to this collection, excluding the
+  /// current user
+  List<CollectionShare> get shares;
+
   /// Return the URL of the cover image if available
   ///
   /// The [width] and [height] are provided as a hint only, implementations are
diff --git a/app/lib/entity/collection/adapter.dart b/app/lib/entity/collection/adapter.dart
index db703281..a348e089 100644
--- a/app/lib/entity/collection/adapter.dart
+++ b/app/lib/entity/collection/adapter.dart
@@ -14,11 +14,14 @@ import 'package:nc_photos/entity/collection/content_provider/memory.dart';
 import 'package:nc_photos/entity/collection/content_provider/nc_album.dart';
 import 'package:nc_photos/entity/collection/content_provider/person.dart';
 import 'package:nc_photos/entity/collection/content_provider/tag.dart';
+import 'package:nc_photos/entity/collection/util.dart';
 import 'package:nc_photos/entity/collection_item.dart';
 import 'package:nc_photos/entity/collection_item/new_item.dart';
 import 'package:nc_photos/entity/collection_item/util.dart';
 import 'package:nc_photos/entity/file_descriptor.dart';
+import 'package:nc_photos/entity/sharee.dart';
 import 'package:nc_photos/or_null.dart';
+import 'package:np_common/ci_string.dart';
 import 'package:np_common/type.dart';
 
 abstract class CollectionAdapter {
@@ -71,6 +74,18 @@ abstract class CollectionAdapter {
     required ValueChanged<Collection> onCollectionUpdated,
   });
 
+  /// Share the collection with [sharee]
+  Future<CollectionShareResult> share(
+    Sharee sharee, {
+    required ValueChanged<Collection> onCollectionUpdated,
+  });
+
+  /// Unshare the collection with a user
+  Future<CollectionShareResult> unshare(
+    CiString userId, {
+    required ValueChanged<Collection> onCollectionUpdated,
+  });
+
   /// Convert a [NewCollectionItem] to an adapted one
   Future<CollectionItem> adaptToNewItem(NewCollectionItem original);
 
diff --git a/app/lib/entity/collection/adapter/read_only_adapter.dart b/app/lib/entity/collection/adapter/adapter_mixin.dart
similarity index 63%
rename from app/lib/entity/collection/adapter/read_only_adapter.dart
rename to app/lib/entity/collection/adapter/adapter_mixin.dart
index e5766f18..8deda148 100644
--- a/app/lib/entity/collection/adapter/read_only_adapter.dart
+++ b/app/lib/entity/collection/adapter/adapter_mixin.dart
@@ -1,14 +1,17 @@
 import 'package:flutter/foundation.dart';
 import 'package:nc_photos/entity/collection.dart';
 import 'package:nc_photos/entity/collection/adapter.dart';
+import 'package:nc_photos/entity/collection/util.dart';
 import 'package:nc_photos/entity/collection_item.dart';
 import 'package:nc_photos/entity/collection_item/util.dart';
 import 'package:nc_photos/entity/file_descriptor.dart';
+import 'package:nc_photos/entity/sharee.dart';
 import 'package:nc_photos/or_null.dart';
+import 'package:np_common/ci_string.dart';
 import 'package:np_common/type.dart';
 
 /// A read-only collection that does not support modifying its items
-mixin CollectionReadOnlyAdapter implements CollectionAdapter {
+mixin CollectionAdapterReadOnlyTag implements CollectionAdapter {
   @override
   Future<int> addFiles(
     List<FileDescriptor> files, {
@@ -48,3 +51,28 @@ mixin CollectionReadOnlyAdapter implements CollectionAdapter {
   Future<Collection?> updatePostLoad(List<CollectionItem> items) =>
       Future.value(null);
 }
+
+mixin CollectionAdapterUnremovableTag implements CollectionAdapter {
+  @override
+  Future<void> remove() {
+    throw UnsupportedError("Operation not supported");
+  }
+}
+
+mixin CollectionAdapterUnshareableTag implements CollectionAdapter {
+  @override
+  Future<CollectionShareResult> share(
+    Sharee sharee, {
+    required ValueChanged<Collection> onCollectionUpdated,
+  }) {
+    throw UnsupportedError("Operation not supported");
+  }
+
+  @override
+  Future<CollectionShareResult> unshare(
+    CiString userId, {
+    required ValueChanged<Collection> onCollectionUpdated,
+  }) {
+    throw UnsupportedError("Operation not supported");
+  }
+}
diff --git a/app/lib/entity/collection/adapter/album.dart b/app/lib/entity/collection/adapter/album.dart
index 36486eb5..b4b6352c 100644
--- a/app/lib/entity/collection/adapter/album.dart
+++ b/app/lib/entity/collection/adapter/album.dart
@@ -2,6 +2,7 @@ import 'package:collection/collection.dart';
 import 'package:flutter/foundation.dart';
 import 'package:logging/logging.dart';
 import 'package:nc_photos/account.dart';
+import 'package:nc_photos/debug_util.dart';
 import 'package:nc_photos/di_container.dart';
 import 'package:nc_photos/entity/album/cover_provider.dart';
 import 'package:nc_photos/entity/album/item.dart';
@@ -10,12 +11,14 @@ import 'package:nc_photos/entity/collection.dart';
 import 'package:nc_photos/entity/collection/adapter.dart';
 import 'package:nc_photos/entity/collection/builder.dart';
 import 'package:nc_photos/entity/collection/content_provider/album.dart';
+import 'package:nc_photos/entity/collection/util.dart';
 import 'package:nc_photos/entity/collection_item.dart';
 import 'package:nc_photos/entity/collection_item/album_item_adapter.dart';
 import 'package:nc_photos/entity/collection_item/new_item.dart';
 import 'package:nc_photos/entity/collection_item/util.dart';
 import 'package:nc_photos/entity/file.dart';
 import 'package:nc_photos/entity/file_descriptor.dart';
+import 'package:nc_photos/entity/sharee.dart';
 import 'package:nc_photos/iterable_extension.dart';
 import 'package:nc_photos/object_extension.dart';
 import 'package:nc_photos/or_null.dart';
@@ -23,9 +26,12 @@ import 'package:nc_photos/use_case/album/add_file_to_album.dart';
 import 'package:nc_photos/use_case/album/edit_album.dart';
 import 'package:nc_photos/use_case/album/remove_album.dart';
 import 'package:nc_photos/use_case/album/remove_from_album.dart';
+import 'package:nc_photos/use_case/album/share_album_with_user.dart';
+import 'package:nc_photos/use_case/album/unshare_album_with_user.dart';
 import 'package:nc_photos/use_case/preprocess_album.dart';
 import 'package:nc_photos/use_case/update_album_with_actual_items.dart';
 import 'package:np_codegen/np_codegen.dart';
+import 'package:np_common/ci_string.dart';
 import 'package:np_common/type.dart';
 import 'package:tuple/tuple.dart';
 
@@ -173,6 +179,50 @@ class CollectionAlbumAdapter implements CollectionAdapter {
     }
   }
 
+  @override
+  Future<CollectionShareResult> share(
+    Sharee sharee, {
+    required ValueChanged<Collection> onCollectionUpdated,
+  }) async {
+    var fileFailed = false;
+    final newAlbum = await ShareAlbumWithUser(_c.shareRepo, _c.albumRepo)(
+      account,
+      _provider.album,
+      sharee,
+      onShareFileFailed: (f, e, stackTrace) {
+        _log.severe("[share] Failed to share file: ${logFilename(f.path)}", e,
+            stackTrace);
+        fileFailed = true;
+      },
+    );
+    onCollectionUpdated(CollectionBuilder.byAlbum(account, newAlbum));
+    return fileFailed
+        ? CollectionShareResult.partial
+        : CollectionShareResult.ok;
+  }
+
+  @override
+  Future<CollectionShareResult> unshare(
+    CiString userId, {
+    required ValueChanged<Collection> onCollectionUpdated,
+  }) async {
+    var fileFailed = false;
+    final newAlbum = await UnshareAlbumWithUser(_c)(
+      account,
+      _provider.album,
+      userId,
+      onUnshareFileFailed: (f, e, stackTrace) {
+        _log.severe("[unshare] Failed to unshare file: ${logFilename(f.path)}",
+            e, stackTrace);
+        fileFailed = true;
+      },
+    );
+    onCollectionUpdated(CollectionBuilder.byAlbum(account, newAlbum));
+    return fileFailed
+        ? CollectionShareResult.partial
+        : CollectionShareResult.ok;
+  }
+
   @override
   Future<CollectionItem> adaptToNewItem(NewCollectionItem original) async {
     if (original is NewCollectionFileItem) {
diff --git a/app/lib/entity/collection/adapter/location_group.dart b/app/lib/entity/collection/adapter/location_group.dart
index 3f012101..e287dfe6 100644
--- a/app/lib/entity/collection/adapter/location_group.dart
+++ b/app/lib/entity/collection/adapter/location_group.dart
@@ -2,7 +2,7 @@ import 'package:nc_photos/account.dart';
 import 'package:nc_photos/di_container.dart';
 import 'package:nc_photos/entity/collection.dart';
 import 'package:nc_photos/entity/collection/adapter.dart';
-import 'package:nc_photos/entity/collection/adapter/read_only_adapter.dart';
+import 'package:nc_photos/entity/collection/adapter/adapter_mixin.dart';
 import 'package:nc_photos/entity/collection/content_provider/location_group.dart';
 import 'package:nc_photos/entity/collection_item.dart';
 import 'package:nc_photos/entity/collection_item/basic_item.dart';
@@ -11,7 +11,10 @@ import 'package:nc_photos/entity/file_util.dart' as file_util;
 import 'package:nc_photos/use_case/list_location_file.dart';
 
 class CollectionLocationGroupAdapter
-    with CollectionReadOnlyAdapter
+    with
+        CollectionAdapterReadOnlyTag,
+        CollectionAdapterUnremovableTag,
+        CollectionAdapterUnshareableTag
     implements CollectionAdapter {
   CollectionLocationGroupAdapter(this._c, this.account, this.collection)
       : assert(require(_c)),
@@ -43,11 +46,6 @@ class CollectionLocationGroupAdapter
     }
   }
 
-  @override
-  Future<void> remove() {
-    throw UnsupportedError("Operation not supported");
-  }
-
   @override
   bool isPermitted(CollectionCapability capability) =>
       _provider.capabilities.contains(capability);
diff --git a/app/lib/entity/collection/adapter/memory.dart b/app/lib/entity/collection/adapter/memory.dart
index 53a16a4d..eea3948f 100644
--- a/app/lib/entity/collection/adapter/memory.dart
+++ b/app/lib/entity/collection/adapter/memory.dart
@@ -2,7 +2,7 @@ import 'package:nc_photos/account.dart';
 import 'package:nc_photos/di_container.dart';
 import 'package:nc_photos/entity/collection.dart';
 import 'package:nc_photos/entity/collection/adapter.dart';
-import 'package:nc_photos/entity/collection/adapter/read_only_adapter.dart';
+import 'package:nc_photos/entity/collection/adapter/adapter_mixin.dart';
 import 'package:nc_photos/entity/collection/content_provider/memory.dart';
 import 'package:nc_photos/entity/collection_item.dart';
 import 'package:nc_photos/entity/collection_item/basic_item.dart';
@@ -11,7 +11,10 @@ import 'package:nc_photos/entity/file_util.dart' as file_util;
 import 'package:nc_photos/use_case/list_location_file.dart';
 
 class CollectionMemoryAdapter
-    with CollectionReadOnlyAdapter
+    with
+        CollectionAdapterReadOnlyTag,
+        CollectionAdapterUnremovableTag,
+        CollectionAdapterUnshareableTag
     implements CollectionAdapter {
   CollectionMemoryAdapter(this._c, this.account, this.collection)
       : assert(require(_c)),
@@ -42,11 +45,6 @@ class CollectionMemoryAdapter
     }
   }
 
-  @override
-  Future<void> remove() {
-    throw UnsupportedError("Operation not supported");
-  }
-
   @override
   bool isPermitted(CollectionCapability capability) =>
       _provider.capabilities.contains(capability);
diff --git a/app/lib/entity/collection/adapter/nc_album.dart b/app/lib/entity/collection/adapter/nc_album.dart
index 28072cf7..d3f4cd5c 100644
--- a/app/lib/entity/collection/adapter/nc_album.dart
+++ b/app/lib/entity/collection/adapter/nc_album.dart
@@ -5,6 +5,7 @@ import 'package:nc_photos/account.dart';
 import 'package:nc_photos/di_container.dart';
 import 'package:nc_photos/entity/collection.dart';
 import 'package:nc_photos/entity/collection/adapter.dart';
+import 'package:nc_photos/entity/collection/adapter/adapter_mixin.dart';
 import 'package:nc_photos/entity/collection/content_provider/nc_album.dart';
 import 'package:nc_photos/entity/collection_item.dart';
 import 'package:nc_photos/entity/collection_item/basic_item.dart';
@@ -27,7 +28,9 @@ import 'package:np_common/type.dart';
 part 'nc_album.g.dart';
 
 @npLog
-class CollectionNcAlbumAdapter implements CollectionAdapter {
+class CollectionNcAlbumAdapter
+    with CollectionAdapterUnshareableTag
+    implements CollectionAdapter {
   CollectionNcAlbumAdapter(this._c, this.account, this.collection)
       : assert(require(_c)),
         _provider = collection.contentProvider as CollectionNcAlbumProvider;
diff --git a/app/lib/entity/collection/adapter/person.dart b/app/lib/entity/collection/adapter/person.dart
index 926b202d..a4527dd2 100644
--- a/app/lib/entity/collection/adapter/person.dart
+++ b/app/lib/entity/collection/adapter/person.dart
@@ -2,7 +2,7 @@ import 'package:nc_photos/account.dart';
 import 'package:nc_photos/di_container.dart';
 import 'package:nc_photos/entity/collection.dart';
 import 'package:nc_photos/entity/collection/adapter.dart';
-import 'package:nc_photos/entity/collection/adapter/read_only_adapter.dart';
+import 'package:nc_photos/entity/collection/adapter/adapter_mixin.dart';
 import 'package:nc_photos/entity/collection/content_provider/person.dart';
 import 'package:nc_photos/entity/collection_item.dart';
 import 'package:nc_photos/entity/collection_item/basic_item.dart';
@@ -12,7 +12,10 @@ import 'package:nc_photos/use_case/list_face.dart';
 import 'package:nc_photos/use_case/populate_person.dart';
 
 class CollectionPersonAdapter
-    with CollectionReadOnlyAdapter
+    with
+        CollectionAdapterReadOnlyTag,
+        CollectionAdapterUnremovableTag,
+        CollectionAdapterUnshareableTag
     implements CollectionAdapter {
   CollectionPersonAdapter(this._c, this.account, this.collection)
       : assert(require(_c)),
@@ -45,11 +48,6 @@ class CollectionPersonAdapter
     }
   }
 
-  @override
-  Future<void> remove() {
-    throw UnsupportedError("Operation not supported");
-  }
-
   @override
   bool isPermitted(CollectionCapability capability) =>
       _provider.capabilities.contains(capability);
diff --git a/app/lib/entity/collection/adapter/tag.dart b/app/lib/entity/collection/adapter/tag.dart
index 29135ac5..1226c181 100644
--- a/app/lib/entity/collection/adapter/tag.dart
+++ b/app/lib/entity/collection/adapter/tag.dart
@@ -2,14 +2,17 @@ import 'package:nc_photos/account.dart';
 import 'package:nc_photos/di_container.dart';
 import 'package:nc_photos/entity/collection.dart';
 import 'package:nc_photos/entity/collection/adapter.dart';
-import 'package:nc_photos/entity/collection/adapter/read_only_adapter.dart';
+import 'package:nc_photos/entity/collection/adapter/adapter_mixin.dart';
 import 'package:nc_photos/entity/collection/content_provider/tag.dart';
 import 'package:nc_photos/entity/collection_item.dart';
 import 'package:nc_photos/entity/collection_item/basic_item.dart';
 import 'package:nc_photos/use_case/list_tagged_file.dart';
 
 class CollectionTagAdapter
-    with CollectionReadOnlyAdapter
+    with
+        CollectionAdapterReadOnlyTag,
+        CollectionAdapterUnremovableTag,
+        CollectionAdapterUnshareableTag
     implements CollectionAdapter {
   CollectionTagAdapter(this._c, this.account, this.collection)
       : assert(require(_c)),
@@ -32,11 +35,6 @@ class CollectionTagAdapter
     }
   }
 
-  @override
-  Future<void> remove() {
-    throw UnsupportedError("Operation not supported");
-  }
-
   @override
   bool isPermitted(CollectionCapability capability) =>
       _provider.capabilities.contains(capability);
diff --git a/app/lib/entity/collection/content_provider/album.dart b/app/lib/entity/collection/content_provider/album.dart
index 9914fa90..93c62bad 100644
--- a/app/lib/entity/collection/content_provider/album.dart
+++ b/app/lib/entity/collection/content_provider/album.dart
@@ -5,6 +5,7 @@ import 'package:nc_photos/api/api_util.dart' as api_util;
 import 'package:nc_photos/entity/album.dart';
 import 'package:nc_photos/entity/album/provider.dart';
 import 'package:nc_photos/entity/collection.dart';
+import 'package:nc_photos/entity/collection/util.dart';
 import 'package:nc_photos/entity/collection_item/util.dart';
 import 'package:to_string/to_string.dart';
 
@@ -52,6 +53,7 @@ class CollectionAlbumProvider
           CollectionCapability.manualItem,
           CollectionCapability.manualSort,
           CollectionCapability.labelItem,
+          CollectionCapability.share,
         ],
       ];
 
@@ -66,6 +68,17 @@ class CollectionAlbumProvider
   @override
   CollectionItemSort get itemSort => album.sortProvider.toCollectionItemSort();
 
+  @override
+  List<CollectionShare> get shares =>
+      album.shares
+          ?.where((s) => s.userId != account.userId)
+          .map((s) => CollectionShare(
+                userId: s.userId,
+                username: s.displayName ?? s.userId.raw,
+              ))
+          .toList() ??
+      const [];
+
   @override
   String? getCoverUrl(
     int width,
diff --git a/app/lib/entity/collection/content_provider/location_group.dart b/app/lib/entity/collection/content_provider/location_group.dart
index 6316eb99..cf809b48 100644
--- a/app/lib/entity/collection/content_provider/location_group.dart
+++ b/app/lib/entity/collection/content_provider/location_group.dart
@@ -2,6 +2,7 @@ import 'package:equatable/equatable.dart';
 import 'package:nc_photos/account.dart';
 import 'package:nc_photos/api/api_util.dart' as api_util;
 import 'package:nc_photos/entity/collection.dart';
+import 'package:nc_photos/entity/collection/util.dart';
 import 'package:nc_photos/entity/collection_item/util.dart';
 import 'package:nc_photos/use_case/list_location_group.dart';
 
@@ -31,6 +32,9 @@ class CollectionLocationGroupProvider
   @override
   CollectionItemSort get itemSort => CollectionItemSort.dateDescending;
 
+  @override
+  List<CollectionShare> get shares => [];
+
   @override
   String? getCoverUrl(
     int width,
diff --git a/app/lib/entity/collection/content_provider/memory.dart b/app/lib/entity/collection/content_provider/memory.dart
index c8ed13c5..a8fcfdf3 100644
--- a/app/lib/entity/collection/content_provider/memory.dart
+++ b/app/lib/entity/collection/content_provider/memory.dart
@@ -2,6 +2,7 @@ import 'package:equatable/equatable.dart';
 import 'package:nc_photos/account.dart';
 import 'package:nc_photos/api/api_util.dart' as api_util;
 import 'package:nc_photos/entity/collection.dart';
+import 'package:nc_photos/entity/collection/util.dart';
 import 'package:nc_photos/entity/collection_item/util.dart';
 import 'package:nc_photos/entity/file_descriptor.dart';
 import 'package:nc_photos/object_extension.dart';
@@ -39,6 +40,9 @@ class CollectionMemoryProvider
   @override
   CollectionItemSort get itemSort => CollectionItemSort.dateDescending;
 
+  @override
+  List<CollectionShare> get shares => [];
+
   @override
   String? getCoverUrl(
     int width,
diff --git a/app/lib/entity/collection/content_provider/nc_album.dart b/app/lib/entity/collection/content_provider/nc_album.dart
index cd22d7fb..f2b00286 100644
--- a/app/lib/entity/collection/content_provider/nc_album.dart
+++ b/app/lib/entity/collection/content_provider/nc_album.dart
@@ -4,6 +4,7 @@ import 'package:equatable/equatable.dart';
 import 'package:nc_photos/account.dart';
 import 'package:nc_photos/api/api_util.dart' as api_util;
 import 'package:nc_photos/entity/collection.dart';
+import 'package:nc_photos/entity/collection/util.dart';
 import 'package:nc_photos/entity/collection_item/util.dart';
 import 'package:nc_photos/entity/nc_album.dart';
 import 'package:to_string/to_string.dart';
@@ -45,6 +46,9 @@ class CollectionNcAlbumProvider
   @override
   CollectionItemSort get itemSort => CollectionItemSort.dateDescending;
 
+  @override
+  List<CollectionShare> get shares => [];
+
   @override
   String? getCoverUrl(
     int width,
diff --git a/app/lib/entity/collection/content_provider/person.dart b/app/lib/entity/collection/content_provider/person.dart
index 16e7efae..f9be868c 100644
--- a/app/lib/entity/collection/content_provider/person.dart
+++ b/app/lib/entity/collection/content_provider/person.dart
@@ -5,6 +5,7 @@ import 'package:equatable/equatable.dart';
 import 'package:nc_photos/account.dart';
 import 'package:nc_photos/api/api_util.dart' as api_util;
 import 'package:nc_photos/entity/collection.dart';
+import 'package:nc_photos/entity/collection/util.dart';
 import 'package:nc_photos/entity/collection_item/util.dart';
 import 'package:nc_photos/entity/person.dart';
 
@@ -34,6 +35,9 @@ class CollectionPersonProvider
   @override
   CollectionItemSort get itemSort => CollectionItemSort.dateDescending;
 
+  @override
+  List<CollectionShare> get shares => [];
+
   @override
   String? getCoverUrl(
     int width,
diff --git a/app/lib/entity/collection/content_provider/tag.dart b/app/lib/entity/collection/content_provider/tag.dart
index 23bc98f8..729160b7 100644
--- a/app/lib/entity/collection/content_provider/tag.dart
+++ b/app/lib/entity/collection/content_provider/tag.dart
@@ -2,6 +2,7 @@ import 'package:clock/clock.dart';
 import 'package:equatable/equatable.dart';
 import 'package:nc_photos/account.dart';
 import 'package:nc_photos/entity/collection.dart';
+import 'package:nc_photos/entity/collection/util.dart';
 import 'package:nc_photos/entity/collection_item/util.dart';
 import 'package:nc_photos/entity/tag.dart';
 
@@ -31,6 +32,9 @@ class CollectionTagProvider
   @override
   CollectionItemSort get itemSort => CollectionItemSort.dateDescending;
 
+  @override
+  List<CollectionShare> get shares => [];
+
   @override
   String? getCoverUrl(
     int width,
diff --git a/app/lib/entity/collection/util.dart b/app/lib/entity/collection/util.dart
index a8b7f07c..905cec22 100644
--- a/app/lib/entity/collection/util.dart
+++ b/app/lib/entity/collection/util.dart
@@ -1,7 +1,12 @@
 import 'package:collection/collection.dart';
+import 'package:equatable/equatable.dart';
 import 'package:nc_photos/entity/collection.dart';
+import 'package:np_common/ci_string.dart';
+import 'package:to_string/to_string.dart';
 import 'package:tuple/tuple.dart';
 
+part 'util.g.dart';
+
 enum CollectionSort {
   dateDescending,
   dateAscending,
@@ -14,6 +19,28 @@ enum CollectionSort {
   }
 }
 
+@toString
+class CollectionShare with EquatableMixin {
+  const CollectionShare({
+    required this.userId,
+    required this.username,
+  });
+
+  @override
+  String toString() => _$toString();
+
+  @override
+  List<Object?> get props => [userId, username];
+
+  final CiString userId;
+  final String username;
+}
+
+enum CollectionShareResult {
+  ok,
+  partial,
+}
+
 extension CollectionListExtension on Iterable<Collection> {
   List<Collection> sortedBy(CollectionSort by) {
     return map<Tuple2<Comparable, Collection>>((e) {
diff --git a/app/lib/entity/collection/util.g.dart b/app/lib/entity/collection/util.g.dart
new file mode 100644
index 00000000..ededd4c9
--- /dev/null
+++ b/app/lib/entity/collection/util.g.dart
@@ -0,0 +1,14 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'util.dart';
+
+// **************************************************************************
+// ToStringGenerator
+// **************************************************************************
+
+extension _$CollectionShareToString on CollectionShare {
+  String _$toString() {
+    // ignore: unnecessary_string_interpolations
+    return "CollectionShare {userId: $userId, username: $username}";
+  }
+}
diff --git a/app/lib/exception.dart b/app/lib/exception.dart
index 714edf01..5f7444b7 100644
--- a/app/lib/exception.dart
+++ b/app/lib/exception.dart
@@ -103,3 +103,18 @@ class AlbumItemPermissionException implements Exception {
 
   final dynamic message;
 }
+
+class CollectionPartialShareException implements Exception {
+  const CollectionPartialShareException([this.message]);
+
+  @override
+  String toString() {
+    if (message == null) {
+      return "CollectionPartialShareException";
+    } else {
+      return "CollectionPartialShareException: $message";
+    }
+  }
+
+  final dynamic message;
+}
diff --git a/app/lib/suggester.dart b/app/lib/suggester.dart
new file mode 100644
index 00000000..20f0dc07
--- /dev/null
+++ b/app/lib/suggester.dart
@@ -0,0 +1,57 @@
+import 'package:collection/collection.dart';
+import 'package:flutter/foundation.dart';
+import 'package:logging/logging.dart';
+import 'package:nc_photos/iterable_extension.dart';
+import 'package:np_codegen/np_codegen.dart';
+import 'package:np_common/ci_string.dart';
+import 'package:tuple/tuple.dart';
+import 'package:woozy_search/woozy_search.dart';
+
+part 'suggester.g.dart';
+
+@npLog
+class Suggester<T> {
+  Suggester({
+    required this.items,
+    required this.itemToKeywords,
+    int maxResult = 5,
+  }) : _searcher = Woozy(limit: maxResult) {
+    for (final a in items) {
+      for (final k in itemToKeywords(a)) {
+        _searcher.addEntry(k.toCaseInsensitiveString(), value: a);
+      }
+    }
+  }
+
+  List<T> search(CiString phrase) {
+    final results = _searcher.search(phrase.toCaseInsensitiveString());
+    if (kDebugMode) {
+      final str = results.map((e) => "${e.score}: ${e.text}").join("\n");
+      _log.info("[search] Search '$phrase':\n$str");
+    }
+    final matches = results
+        .where((e) => e.score > 0)
+        .map((e) {
+          if (itemToKeywords(e.value as T).any((k) => k.startsWith(phrase))) {
+            // prefer names that start exactly with the search phrase
+            return Tuple2(e.score + 1, e.value as T);
+          } else {
+            return Tuple2(e.score, e.value as T);
+          }
+        })
+        .sorted((a, b) => a.item1.compareTo(b.item1))
+        .reversed
+        .distinctIf(
+          (a, b) => identical(a.item2, b.item2),
+          (a) => a.item2.hashCode,
+        )
+        .map((e) => e.item2)
+        .toList();
+    return matches;
+  }
+
+  final List<T> items;
+  final List<CiString> Function(T item) itemToKeywords;
+
+  final Woozy _searcher;
+}
diff --git a/app/lib/suggester.g.dart b/app/lib/suggester.g.dart
new file mode 100644
index 00000000..9f60e8d5
--- /dev/null
+++ b/app/lib/suggester.g.dart
@@ -0,0 +1,14 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'suggester.dart';
+
+// **************************************************************************
+// NpLogGenerator
+// **************************************************************************
+
+extension _$SuggesterNpLog on Suggester {
+  // ignore: unused_element
+  Logger get _log => log;
+
+  static final log = Logger("suggester.Suggester");
+}
diff --git a/app/lib/use_case/album/remove_album.dart b/app/lib/use_case/album/remove_album.dart
index 46f07573..b4c6c23f 100644
--- a/app/lib/use_case/album/remove_album.dart
+++ b/app/lib/use_case/album/remove_album.dart
@@ -6,10 +6,10 @@ import 'package:nc_photos/entity/album/item.dart';
 import 'package:nc_photos/entity/album/provider.dart';
 import 'package:nc_photos/entity/share.dart';
 import 'package:nc_photos/or_null.dart';
+import 'package:nc_photos/use_case/album/unshare_file_from_album.dart';
 import 'package:nc_photos/use_case/list_share.dart';
 import 'package:nc_photos/use_case/remove.dart';
 import 'package:nc_photos/use_case/remove_share.dart';
-import 'package:nc_photos/use_case/unshare_file_from_album.dart';
 import 'package:nc_photos/use_case/update_album.dart';
 import 'package:np_codegen/np_codegen.dart';
 
diff --git a/app/lib/use_case/album/remove_from_album.dart b/app/lib/use_case/album/remove_from_album.dart
index d9af6ad7..cf8deb56 100644
--- a/app/lib/use_case/album/remove_from_album.dart
+++ b/app/lib/use_case/album/remove_from_album.dart
@@ -10,8 +10,8 @@ import 'package:nc_photos/entity/file.dart';
 import 'package:nc_photos/entity/file_descriptor.dart';
 import 'package:nc_photos/exception.dart';
 import 'package:nc_photos/iterable_extension.dart';
+import 'package:nc_photos/use_case/album/unshare_file_from_album.dart';
 import 'package:nc_photos/use_case/preprocess_album.dart';
-import 'package:nc_photos/use_case/unshare_file_from_album.dart';
 import 'package:nc_photos/use_case/update_album.dart';
 import 'package:nc_photos/use_case/update_album_with_actual_items.dart';
 import 'package:np_codegen/np_codegen.dart';
diff --git a/app/lib/use_case/share_album_with_user.dart b/app/lib/use_case/album/share_album_with_user.dart
similarity index 91%
rename from app/lib/use_case/share_album_with_user.dart
rename to app/lib/use_case/album/share_album_with_user.dart
index 2b02beb2..342367c9 100644
--- a/app/lib/use_case/share_album_with_user.dart
+++ b/app/lib/use_case/album/share_album_with_user.dart
@@ -13,6 +13,7 @@ import 'package:nc_photos/use_case/create_share.dart';
 import 'package:nc_photos/use_case/update_album.dart';
 import 'package:np_codegen/np_codegen.dart';
 import 'package:np_common/ci_string.dart';
+import 'package:np_common/type.dart';
 
 part 'share_album_with_user.g.dart';
 
@@ -24,7 +25,7 @@ class ShareAlbumWithUser {
     Account account,
     Album album,
     Sharee sharee, {
-    void Function(File)? onShareFileFailed,
+    ErrorWithValueHandler<File>? onShareFileFailed,
   }) async {
     assert(album.provider is AlbumStaticProvider);
     final newShares = (album.shares ?? [])
@@ -55,7 +56,7 @@ class ShareAlbumWithUser {
     Account account,
     Album album,
     CiString shareWith, {
-    void Function(File)? onShareFileFailed,
+    ErrorWithValueHandler<File>? onShareFileFailed,
   }) async {
     final files = AlbumStaticProvider.of(album)
         .items
@@ -70,7 +71,7 @@ class ShareAlbumWithUser {
           "[_createFileShares] Failed sharing album file '${logFilename(album.albumFile?.path)}' with '$shareWith'",
           e,
           stackTrace);
-      onShareFileFailed?.call(album.albumFile!);
+      onShareFileFailed?.call(album.albumFile!, e, stackTrace);
     }
     for (final f in files) {
       _log.info("[_createFileShares] Sharing '${f.path}' with '$shareWith'");
@@ -81,7 +82,7 @@ class ShareAlbumWithUser {
             "[_createFileShares] Failed sharing file '${logFilename(f.path)}' with '$shareWith'",
             e,
             stackTrace);
-        onShareFileFailed?.call(f);
+        onShareFileFailed?.call(f, e, stackTrace);
       }
     }
   }
diff --git a/app/lib/use_case/share_album_with_user.g.dart b/app/lib/use_case/album/share_album_with_user.g.dart
similarity index 84%
rename from app/lib/use_case/share_album_with_user.g.dart
rename to app/lib/use_case/album/share_album_with_user.g.dart
index 33af6875..3fe70319 100644
--- a/app/lib/use_case/share_album_with_user.g.dart
+++ b/app/lib/use_case/album/share_album_with_user.g.dart
@@ -11,5 +11,5 @@ extension _$ShareAlbumWithUserNpLog on ShareAlbumWithUser {
   Logger get _log => log;
 
   static final log =
-      Logger("use_case.share_album_with_user.ShareAlbumWithUser");
+      Logger("use_case.album.share_album_with_user.ShareAlbumWithUser");
 }
diff --git a/app/lib/use_case/unshare_album_with_user.dart b/app/lib/use_case/album/unshare_album_with_user.dart
similarity index 90%
rename from app/lib/use_case/unshare_album_with_user.dart
rename to app/lib/use_case/album/unshare_album_with_user.dart
index be9b1e26..58e8d620 100644
--- a/app/lib/use_case/unshare_album_with_user.dart
+++ b/app/lib/use_case/album/unshare_album_with_user.dart
@@ -7,12 +7,13 @@ import 'package:nc_photos/entity/album/item.dart';
 import 'package:nc_photos/entity/album/provider.dart';
 import 'package:nc_photos/entity/share.dart';
 import 'package:nc_photos/or_null.dart';
+import 'package:nc_photos/use_case/album/unshare_file_from_album.dart';
 import 'package:nc_photos/use_case/list_share.dart';
 import 'package:nc_photos/use_case/remove_share.dart';
-import 'package:nc_photos/use_case/unshare_file_from_album.dart';
 import 'package:nc_photos/use_case/update_album.dart';
 import 'package:np_codegen/np_codegen.dart';
 import 'package:np_common/ci_string.dart';
+import 'package:np_common/type.dart';
 
 part 'unshare_album_with_user.g.dart';
 
@@ -31,7 +32,7 @@ class UnshareAlbumWithUser {
     Account account,
     Album album,
     CiString shareWith, {
-    void Function(Share)? onUnshareFileFailed,
+    ErrorWithValueHandler<Share>? onUnshareFileFailed,
   }) async {
     assert(album.provider is AlbumStaticProvider);
     // remove the share from album file
@@ -59,7 +60,7 @@ class UnshareAlbumWithUser {
     Account account,
     Album album,
     CiString shareWith, {
-    void Function(Share)? onUnshareFileFailed,
+    ErrorWithValueHandler<Share>? onUnshareFileFailed,
   }) async {
     // remove share from the album file
     final albumShares = await ListShare(_c)(account, album.albumFile!);
@@ -71,7 +72,7 @@ class UnshareAlbumWithUser {
             "[_deleteFileShares] Failed unsharing album file '${logFilename(album.albumFile?.path)}' with '$shareWith'",
             e,
             stackTrace);
-        onUnshareFileFailed?.call(s);
+        onUnshareFileFailed?.call(s, e, stackTrace);
       }
     }
 
diff --git a/app/lib/use_case/unshare_album_with_user.g.dart b/app/lib/use_case/album/unshare_album_with_user.g.dart
similarity index 83%
rename from app/lib/use_case/unshare_album_with_user.g.dart
rename to app/lib/use_case/album/unshare_album_with_user.g.dart
index e80f8bff..852e860f 100644
--- a/app/lib/use_case/unshare_album_with_user.g.dart
+++ b/app/lib/use_case/album/unshare_album_with_user.g.dart
@@ -11,5 +11,5 @@ extension _$UnshareAlbumWithUserNpLog on UnshareAlbumWithUser {
   Logger get _log => log;
 
   static final log =
-      Logger("use_case.unshare_album_with_user.UnshareAlbumWithUser");
+      Logger("use_case.album.unshare_album_with_user.UnshareAlbumWithUser");
 }
diff --git a/app/lib/use_case/unshare_file_from_album.dart b/app/lib/use_case/album/unshare_file_from_album.dart
similarity index 94%
rename from app/lib/use_case/unshare_file_from_album.dart
rename to app/lib/use_case/album/unshare_file_from_album.dart
index 94c609cf..3e205d86 100644
--- a/app/lib/use_case/unshare_file_from_album.dart
+++ b/app/lib/use_case/album/unshare_file_from_album.dart
@@ -14,6 +14,7 @@ import 'package:nc_photos/use_case/list_share.dart';
 import 'package:nc_photos/use_case/remove_share.dart';
 import 'package:np_codegen/np_codegen.dart';
 import 'package:np_common/ci_string.dart';
+import 'package:np_common/type.dart';
 
 part 'unshare_file_from_album.g.dart';
 
@@ -35,7 +36,7 @@ class UnshareFileFromAlbum {
     Album album,
     List<File> files,
     List<CiString> unshareWith, {
-    void Function(Share)? onUnshareFileFailed,
+    ErrorWithValueHandler<Share>? onUnshareFileFailed,
   }) async {
     _log.info(
         "[call] Unshare ${files.length} files from album '${album.name}' with ${unshareWith.length} users");
@@ -85,14 +86,14 @@ class UnshareFileFromAlbum {
   }
 
   Future<void> _unshare(Account account, List<Share> shares,
-      void Function(Share)? onUnshareFileFailed) async {
+      ErrorWithValueHandler<Share>? onUnshareFileFailed) async {
     for (final s in shares) {
       try {
         await RemoveShare(_c.shareRepo)(account, s);
       } catch (e, stackTrace) {
         _log.severe(
             "[_unshare] Failed while RemoveShare: ${s.path}", e, stackTrace);
-        onUnshareFileFailed?.call(s);
+        onUnshareFileFailed?.call(s, e, stackTrace);
       }
     }
   }
diff --git a/app/lib/use_case/unshare_file_from_album.g.dart b/app/lib/use_case/album/unshare_file_from_album.g.dart
similarity index 83%
rename from app/lib/use_case/unshare_file_from_album.g.dart
rename to app/lib/use_case/album/unshare_file_from_album.g.dart
index 89680f06..adaae550 100644
--- a/app/lib/use_case/unshare_file_from_album.g.dart
+++ b/app/lib/use_case/album/unshare_file_from_album.g.dart
@@ -11,5 +11,5 @@ extension _$UnshareFileFromAlbumNpLog on UnshareFileFromAlbum {
   Logger get _log => log;
 
   static final log =
-      Logger("use_case.unshare_file_from_album.UnshareFileFromAlbum");
+      Logger("use_case.album.unshare_file_from_album.UnshareFileFromAlbum");
 }
diff --git a/app/lib/use_case/collection/share_collection.dart b/app/lib/use_case/collection/share_collection.dart
new file mode 100644
index 00000000..58130aa2
--- /dev/null
+++ b/app/lib/use_case/collection/share_collection.dart
@@ -0,0 +1,25 @@
+import 'package:flutter/foundation.dart';
+import 'package:nc_photos/account.dart';
+import 'package:nc_photos/di_container.dart';
+import 'package:nc_photos/entity/collection.dart';
+import 'package:nc_photos/entity/collection/adapter.dart';
+import 'package:nc_photos/entity/collection/util.dart';
+import 'package:nc_photos/entity/sharee.dart';
+
+class ShareCollection {
+  const ShareCollection(this._c);
+
+  /// Share the collection with [sharee]
+  Future<CollectionShareResult> call(
+    Account account,
+    Collection collection,
+    Sharee sharee, {
+    required ValueChanged<Collection> onCollectionUpdated,
+  }) =>
+      CollectionAdapter.of(_c, account, collection).share(
+        sharee,
+        onCollectionUpdated: onCollectionUpdated,
+      );
+
+  final DiContainer _c;
+}
diff --git a/app/lib/use_case/collection/unshare_collection.dart b/app/lib/use_case/collection/unshare_collection.dart
new file mode 100644
index 00000000..ed2a4270
--- /dev/null
+++ b/app/lib/use_case/collection/unshare_collection.dart
@@ -0,0 +1,25 @@
+import 'package:flutter/foundation.dart';
+import 'package:nc_photos/account.dart';
+import 'package:nc_photos/di_container.dart';
+import 'package:nc_photos/entity/collection.dart';
+import 'package:nc_photos/entity/collection/adapter.dart';
+import 'package:nc_photos/entity/collection/util.dart';
+import 'package:np_common/ci_string.dart';
+
+class UnshareCollection {
+  const UnshareCollection(this._c);
+
+  /// Unshare the collection with a user
+  Future<CollectionShareResult> call(
+    Account account,
+    Collection collection,
+    CiString userId, {
+    required ValueChanged<Collection> onCollectionUpdated,
+  }) =>
+      CollectionAdapter.of(_c, account, collection).unshare(
+        userId,
+        onCollectionUpdated: onCollectionUpdated,
+      );
+
+  final DiContainer _c;
+}
diff --git a/app/lib/widget/collection_browser.dart b/app/lib/widget/collection_browser.dart
index 7cc7a4ba..050f0a10 100644
--- a/app/lib/widget/collection_browser.dart
+++ b/app/lib/widget/collection_browser.dart
@@ -52,6 +52,7 @@ import 'package:nc_photos/widget/photo_list_item.dart';
 import 'package:nc_photos/widget/photo_list_util.dart' as photo_list_util;
 import 'package:nc_photos/widget/selectable_item_list.dart';
 import 'package:nc_photos/widget/selection_app_bar.dart';
+import 'package:nc_photos/widget/share_collection_dialog.dart';
 import 'package:nc_photos/widget/simple_input_dialog.dart';
 import 'package:nc_photos/widget/viewer.dart';
 import 'package:nc_photos/widget/zoom_menu_button.dart';
diff --git a/app/lib/widget/collection_browser/app_bar.dart b/app/lib/widget/collection_browser/app_bar.dart
index 69288e9d..97a2c9a3 100644
--- a/app/lib/widget/collection_browser/app_bar.dart
+++ b/app/lib/widget/collection_browser/app_bar.dart
@@ -16,6 +16,7 @@ class _AppBar extends StatelessWidget {
         final canRename = adapter.isPermitted(CollectionCapability.rename);
         final canManualCover =
             adapter.isPermitted(CollectionCapability.manualCover);
+        final canShare = adapter.isPermitted(CollectionCapability.share);
 
         final actions = <Widget>[
           ZoomMenuButton(
@@ -26,6 +27,12 @@ class _AppBar extends StatelessWidget {
               context.read<PrefController>().setAlbumBrowserZoomLevel(value);
             },
           ),
+          if (canShare)
+            IconButton(
+              onPressed: () => _onSharePressed(context),
+              icon: const Icon(Icons.share),
+              tooltip: L10n.global().shareTooltip,
+            ),
         ];
         if (state.items.isNotEmpty || canRename) {
           actions.add(PopupMenuButton<_MenuOption>(
@@ -107,6 +114,17 @@ class _AppBar extends StatelessWidget {
       Navigator.of(context).pop();
     }
   }
+
+  Future<void> _onSharePressed(BuildContext context) async {
+    final bloc = context.read<_Bloc>();
+    await showDialog(
+      context: context,
+      builder: (_) => ShareCollectionDialog(
+        account: bloc.account,
+        collection: bloc.state.collection,
+      ),
+    );
+  }
 }
 
 class _AppBarCover extends StatelessWidget {
diff --git a/app/lib/widget/share_album_dialog.dart b/app/lib/widget/share_album_dialog.dart
index 785ca676..e406cc80 100644
--- a/app/lib/widget/share_album_dialog.dart
+++ b/app/lib/widget/share_album_dialog.dart
@@ -15,8 +15,8 @@ import 'package:nc_photos/entity/sharee.dart';
 import 'package:nc_photos/exception_util.dart' as exception_util;
 import 'package:nc_photos/k.dart' as k;
 import 'package:nc_photos/snack_bar_manager.dart';
-import 'package:nc_photos/use_case/share_album_with_user.dart';
-import 'package:nc_photos/use_case/unshare_album_with_user.dart';
+import 'package:nc_photos/use_case/album/share_album_with_user.dart';
+import 'package:nc_photos/use_case/album/unshare_album_with_user.dart';
 import 'package:nc_photos/widget/album_share_outlier_browser.dart';
 import 'package:nc_photos/widget/dialog_scaffold.dart';
 import 'package:np_codegen/np_codegen.dart';
@@ -240,7 +240,7 @@ class _ShareAlbumDialogState extends State<ShareAlbumDialog> {
           widget.account,
           _album,
           sharee,
-          onShareFileFailed: (_) {
+          onShareFileFailed: (_, __, ___) {
             hasFailure = true;
           },
         );
@@ -279,7 +279,7 @@ class _ShareAlbumDialogState extends State<ShareAlbumDialog> {
           widget.account,
           _album,
           share.shareWith,
-          onUnshareFileFailed: (_) {
+          onUnshareFileFailed: (_, __, ___) {
             hasFailure = true;
           },
         );
diff --git a/app/lib/widget/share_collection_dialog.dart b/app/lib/widget/share_collection_dialog.dart
new file mode 100644
index 00000000..5dc2ebe5
--- /dev/null
+++ b/app/lib/widget/share_collection_dialog.dart
@@ -0,0 +1,237 @@
+import 'dart:async';
+
+import 'package:collection/collection.dart';
+import 'package:copy_with/copy_with.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:flutter_typeahead/flutter_typeahead.dart';
+import 'package:kiwi/kiwi.dart';
+import 'package:logging/logging.dart';
+import 'package:nc_photos/account.dart';
+import 'package:nc_photos/app_localizations.dart';
+import 'package:nc_photos/controller/account_controller.dart';
+import 'package:nc_photos/controller/collections_controller.dart';
+import 'package:nc_photos/di_container.dart';
+import 'package:nc_photos/entity/collection.dart';
+import 'package:nc_photos/entity/collection/util.dart';
+import 'package:nc_photos/entity/sharee.dart';
+import 'package:nc_photos/exception.dart';
+import 'package:nc_photos/exception_event.dart';
+import 'package:nc_photos/exception_util.dart' as exception_util;
+import 'package:nc_photos/k.dart' as k;
+import 'package:nc_photos/snack_bar_manager.dart';
+import 'package:nc_photos/suggester.dart';
+import 'package:np_codegen/np_codegen.dart';
+import 'package:np_common/ci_string.dart';
+import 'package:to_string/to_string.dart';
+
+part 'share_collection_dialog.g.dart';
+part 'share_collection_dialog/bloc.dart';
+part 'share_collection_dialog/state_event.dart';
+
+typedef _BlocBuilder = BlocBuilder<_Bloc, _State>;
+
+/// Dialog to share a new collection to other user on the same server
+///
+/// Return the created collection, or null if user cancelled
+class ShareCollectionDialog extends StatelessWidget {
+  const ShareCollectionDialog({
+    super.key,
+    required this.account,
+    required this.collection,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return BlocProvider(
+      create: (context) => _Bloc(
+        container: KiwiContainer().resolve<DiContainer>(),
+        account: account,
+        collectionsController:
+            context.read<AccountController>().collectionsController,
+        collection: collection,
+      ),
+      child: const _WrappedShareCollectionDialog(),
+    );
+  }
+
+  final Account account;
+  final Collection collection;
+}
+
+class _WrappedShareCollectionDialog extends StatefulWidget {
+  const _WrappedShareCollectionDialog();
+
+  @override
+  State<StatefulWidget> createState() => _WrappedShareCollectionDialogState();
+}
+
+class _WrappedShareCollectionDialogState
+    extends State<_WrappedShareCollectionDialog> {
+  @override
+  void initState() {
+    super.initState();
+    _bloc.add(const _LoadSharee());
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return MultiBlocListener(
+      listeners: [
+        BlocListener<_Bloc, _State>(
+          listenWhen: (previous, current) => previous.error != current.error,
+          listener: (context, state) {
+            if (state.error != null) {
+              if (state.error!.error is CollectionPartialShareException) {
+                // TODO localize string
+                SnackBarManager().showSnackBar(const SnackBar(
+                  content: Text("Collection shared partially"),
+                  duration: k.snackBarDurationNormal,
+                ));
+              } else {
+                SnackBarManager().showSnackBar(SnackBar(
+                  content:
+                      Text(exception_util.toUserString(state.error!.error)),
+                  duration: k.snackBarDurationNormal,
+                ));
+              }
+            }
+          },
+        ),
+      ],
+      child: _BlocBuilder(
+        buildWhen: (previous, current) =>
+            previous.collection != current.collection ||
+            previous.processingShares != current.processingShares,
+        builder: (context, state) {
+          final shares = {
+            ...state.collection.shares,
+            ...state.processingShares,
+          }.sortedBy((e) => e.username);
+          return SimpleDialog(
+            title: Text(L10n.global().shareAlbumDialogTitle),
+            children: [
+              ...shares.map((s) => _ShareView(
+                    share: s,
+                    isProcessing: state.processingShares.contains(s),
+                    onPressed: () {
+                      _bloc.add(_Unshare(s));
+                    },
+                  )),
+              const _ShareeInputView(),
+            ],
+          );
+        },
+      ),
+    );
+  }
+
+  late final _bloc = context.read<_Bloc>();
+}
+
+class _ShareeInputView extends StatefulWidget {
+  const _ShareeInputView();
+
+  @override
+  State<StatefulWidget> createState() => _ShareeInputViewState();
+}
+
+class _ShareeInputViewState extends State<_ShareeInputView> {
+  @override
+  Widget build(BuildContext context) {
+    return MultiBlocListener(
+      listeners: [
+        BlocListener<_Bloc, _State>(
+          listenWhen: (previous, current) =>
+              previous.shareeSuggester != current.shareeSuggester,
+          listener: (context, state) {
+            // search again
+            if (_lastPattern != null) {
+              _onSearch(_lastPattern!);
+            }
+          },
+        ),
+      ],
+      child: Padding(
+        padding: const EdgeInsets.symmetric(horizontal: 40),
+        child: TypeAheadField<Sharee>(
+          textFieldConfiguration: TextFieldConfiguration(
+            controller: _textController,
+            decoration: InputDecoration(
+              hintText: L10n.global().addUserInputHint,
+            ),
+          ),
+          direction: AxisDirection.up,
+          suggestionsCallback: _onSearch,
+          itemBuilder: (context, suggestion) => ListTile(
+            title: Text(suggestion.label),
+            subtitle: Text(suggestion.shareWith.toString()),
+          ),
+          onSuggestionSelected: _onSuggestionSelected,
+          hideOnEmpty: true,
+          hideOnLoading: true,
+          autoFlipDirection: true,
+        ),
+      ),
+    );
+  }
+
+  Iterable<Sharee> _onSearch(String pattern) {
+    _lastPattern = pattern;
+    final suggester = _bloc.state.shareeSuggester;
+    return suggester?.search(pattern.toCi()) ?? [];
+  }
+
+  void _onSuggestionSelected(Sharee sharee) {
+    _textController.clear();
+    _bloc.add(_Share(sharee));
+  }
+
+  late final _bloc = context.read<_Bloc>();
+  final _textController = TextEditingController();
+
+  String? _lastPattern;
+}
+
+class _ShareView extends StatelessWidget {
+  const _ShareView({
+    required this.share,
+    required this.isProcessing,
+    this.onPressed,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final Widget trailing;
+    if (isProcessing) {
+      trailing = const Padding(
+        padding: EdgeInsetsDirectional.only(end: 12),
+        child: SizedBox(
+          width: 24,
+          height: 24,
+          child: CircularProgressIndicator(),
+        ),
+      );
+    } else {
+      trailing = Checkbox(
+        value: true,
+        onChanged: (_) {},
+      );
+    }
+    return SimpleDialogOption(
+      onPressed: isProcessing ? null : onPressed,
+      child: ListTile(
+        title: Text(share.username),
+        subtitle: Text(share.userId.toString()),
+        // pass through the tap event
+        trailing: IgnorePointer(
+          child: trailing,
+        ),
+      ),
+    );
+  }
+
+  final CollectionShare share;
+  final bool isProcessing;
+  final VoidCallback? onPressed;
+}
diff --git a/app/lib/widget/share_collection_dialog.g.dart b/app/lib/widget/share_collection_dialog.g.dart
new file mode 100644
index 00000000..cbe3acf4
--- /dev/null
+++ b/app/lib/widget/share_collection_dialog.g.dart
@@ -0,0 +1,116 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'share_collection_dialog.dart';
+
+// **************************************************************************
+// CopyWithLintRuleGenerator
+// **************************************************************************
+
+// ignore_for_file: library_private_types_in_public_api, duplicate_ignore
+
+// **************************************************************************
+// CopyWithGenerator
+// **************************************************************************
+
+abstract class $_StateCopyWithWorker {
+  _State call(
+      {Collection? collection,
+      List<CollectionShare>? processingShares,
+      List<Sharee>? sharees,
+      Suggester<Sharee>? shareeSuggester,
+      ExceptionEvent? error});
+}
+
+class _$_StateCopyWithWorkerImpl implements $_StateCopyWithWorker {
+  _$_StateCopyWithWorkerImpl(this.that);
+
+  @override
+  _State call(
+      {dynamic collection,
+      dynamic processingShares,
+      dynamic sharees = copyWithNull,
+      dynamic shareeSuggester = copyWithNull,
+      dynamic error = copyWithNull}) {
+    return _State(
+        collection: collection as Collection? ?? that.collection,
+        processingShares:
+            processingShares as List<CollectionShare>? ?? that.processingShares,
+        sharees:
+            sharees == copyWithNull ? that.sharees : sharees as List<Sharee>?,
+        shareeSuggester: shareeSuggester == copyWithNull
+            ? that.shareeSuggester
+            : shareeSuggester as Suggester<Sharee>?,
+        error: error == copyWithNull ? that.error : error as ExceptionEvent?);
+  }
+
+  final _State that;
+}
+
+extension $_StateCopyWith on _State {
+  $_StateCopyWithWorker get copyWith => _$copyWith;
+  $_StateCopyWithWorker get _$copyWith => _$_StateCopyWithWorkerImpl(this);
+}
+
+// **************************************************************************
+// NpLogGenerator
+// **************************************************************************
+
+extension _$_BlocNpLog on _Bloc {
+  // ignore: unused_element
+  Logger get _log => log;
+
+  static final log = Logger("widget.share_collection_dialog._Bloc");
+}
+
+// **************************************************************************
+// ToStringGenerator
+// **************************************************************************
+
+extension _$_StateToString on _State {
+  String _$toString() {
+    // ignore: unnecessary_string_interpolations
+    return "_State {collection: $collection, processingShares: [length: ${processingShares.length}], sharees: ${sharees == null ? null : "[length: ${sharees!.length}]"}, shareeSuggester: $shareeSuggester, error: $error}";
+  }
+}
+
+extension _$_UpdateCollectionToString on _UpdateCollection {
+  String _$toString() {
+    // ignore: unnecessary_string_interpolations
+    return "_UpdateCollection {collection: $collection}";
+  }
+}
+
+extension _$_LoadShareeToString on _LoadSharee {
+  String _$toString() {
+    // ignore: unnecessary_string_interpolations
+    return "_LoadSharee {}";
+  }
+}
+
+extension _$_RefreshSuggesterToString on _RefreshSuggester {
+  String _$toString() {
+    // ignore: unnecessary_string_interpolations
+    return "_RefreshSuggester {}";
+  }
+}
+
+extension _$_ShareToString on _Share {
+  String _$toString() {
+    // ignore: unnecessary_string_interpolations
+    return "_Share {sharee: $sharee}";
+  }
+}
+
+extension _$_UnshareToString on _Unshare {
+  String _$toString() {
+    // ignore: unnecessary_string_interpolations
+    return "_Unshare {share: $share}";
+  }
+}
+
+extension _$_SetErrorToString on _SetError {
+  String _$toString() {
+    // ignore: unnecessary_string_interpolations
+    return "_SetError {error: $error, stackTrace: $stackTrace}";
+  }
+}
diff --git a/app/lib/widget/share_collection_dialog/bloc.dart b/app/lib/widget/share_collection_dialog/bloc.dart
new file mode 100644
index 00000000..56ad2185
--- /dev/null
+++ b/app/lib/widget/share_collection_dialog/bloc.dart
@@ -0,0 +1,147 @@
+part of '../share_collection_dialog.dart';
+
+@npLog
+class _Bloc extends Bloc<_Event, _State> {
+  _Bloc({
+    required DiContainer container,
+    required this.account,
+    required this.collectionsController,
+    required Collection collection,
+  })  : _c = container,
+        super(_State.init(
+          collection: collection,
+        )) {
+    on<_UpdateCollection>(_onUpdateCollection);
+    on<_LoadSharee>(_onLoadSharee);
+    on<_RefreshSuggester>(_onRefreshSuggester);
+
+    on<_ShareEventTag>((ev, emit) {
+      if (ev is _Share) {
+        return _onShare(ev, emit);
+      } else if (ev is _Unshare) {
+        return _onUnshare(ev, emit);
+      } else {
+        throw UnimplementedError();
+      }
+    });
+
+    on<_SetError>(_onSetError);
+
+    _collectionControllerSubscription = collectionsController.stream.listen(
+      (event) {
+        final c = event.data
+            .firstWhere((d) => state.collection.compareIdentity(d.collection));
+        if (!identical(c, state.collection)) {
+          add(_UpdateCollection(c.collection));
+        }
+      },
+      onError: (e, stackTrace) {
+        add(_SetError(e, stackTrace));
+      },
+    );
+  }
+
+  @override
+  Future<void> close() {
+    _collectionControllerSubscription?.cancel();
+    return super.close();
+  }
+
+  @override
+  void onChange(Change<_State> change) {
+    if (change.currentState.sharees != change.nextState.sharees ||
+        change.currentState.collection != change.nextState.collection ||
+        change.currentState.processingShares !=
+            change.nextState.processingShares) {
+      add(const _RefreshSuggester());
+    }
+    super.onChange(change);
+  }
+
+  @override
+  void onError(Object error, StackTrace stackTrace) {
+    add(_SetError(error, stackTrace));
+    super.onError(error, stackTrace);
+  }
+
+  void _onUpdateCollection(_UpdateCollection ev, Emitter<_State> emit) {
+    _log.info(ev);
+    emit(state.copyWith(collection: ev.collection));
+  }
+
+  Future<void> _onLoadSharee(_LoadSharee ev, Emitter<_State> emit) async {
+    _log.info(ev);
+    final sharees = await _c.shareeRepo.list(account);
+    emit(state.copyWith(sharees: sharees));
+  }
+
+  void _onRefreshSuggester(_RefreshSuggester ev, Emitter<_State> emit) {
+    _log.info(ev);
+    final searchable = state.sharees
+            ?.where((s) =>
+                !state.collection.shares.any((e) => e.userId == s.shareWith))
+            .where((s) =>
+                !state.processingShares.any((e) => e.userId == s.shareWith))
+            .where((s) => s.shareWith != account.userId)
+            .toList() ??
+        [];
+    emit(state.copyWith(
+      shareeSuggester: Suggester<Sharee>(
+        items: searchable,
+        itemToKeywords: (item) => [item.shareWith, item.label.toCi()],
+        maxResult: 10,
+      ),
+    ));
+  }
+
+  Future<void> _onShare(_Share ev, Emitter<_State> emit) async {
+    _log.info(ev);
+    if (state.collection.shares.any((s) => s.userId == ev.sharee.shareWith) ||
+        state.processingShares.any((s) => s.userId == ev.sharee.shareWith)) {
+      _log.fine("[_onShare] Already shared with sharee: ${ev.sharee}");
+      return;
+    }
+    emit(state.copyWith(
+      processingShares: [
+        ...state.processingShares,
+        CollectionShare(
+          userId: ev.sharee.shareWith,
+          username: ev.sharee.label,
+        ),
+      ],
+    ));
+    await collectionsController.share(state.collection, ev.sharee);
+    emit(state.copyWith(
+      processingShares: state.processingShares
+          .where((s) => s.userId != ev.sharee.shareWith)
+          .toList(),
+    ));
+  }
+
+  Future<void> _onUnshare(_Unshare ev, Emitter<_State> emit) async {
+    _log.info(ev);
+    emit(state.copyWith(
+      processingShares: [
+        ...state.processingShares,
+        ev.share,
+      ],
+    ));
+    await collectionsController.unshare(state.collection, ev.share.userId);
+    emit(state.copyWith(
+      processingShares: state.processingShares
+          .where((s) => s.userId != ev.share.userId)
+          .toList(),
+    ));
+  }
+
+  void _onSetError(_SetError ev, Emitter<_State> emit) {
+    _log.info(ev);
+    emit(state.copyWith(error: ExceptionEvent(ev.error, ev.stackTrace)));
+  }
+
+  final DiContainer _c;
+  final Account account;
+  final CollectionsController collectionsController;
+
+  StreamSubscription? _collectionControllerSubscription;
+}
diff --git a/app/lib/widget/share_collection_dialog/state_event.dart b/app/lib/widget/share_collection_dialog/state_event.dart
new file mode 100644
index 00000000..86eea090
--- /dev/null
+++ b/app/lib/widget/share_collection_dialog/state_event.dart
@@ -0,0 +1,96 @@
+part of '../share_collection_dialog.dart';
+
+@genCopyWith
+@toString
+class _State {
+  const _State({
+    required this.collection,
+    required this.processingShares,
+    this.sharees,
+    this.shareeSuggester,
+    this.error,
+  });
+
+  factory _State.init({
+    required Collection collection,
+  }) {
+    return _State(
+      collection: collection,
+      processingShares: const [],
+    );
+  }
+
+  @override
+  String toString() => _$toString();
+
+  final Collection collection;
+  final List<CollectionShare> processingShares;
+
+  final List<Sharee>? sharees;
+  final Suggester<Sharee>? shareeSuggester;
+
+  final ExceptionEvent? error;
+}
+
+abstract class _Event {
+  const _Event();
+}
+
+@toString
+class _UpdateCollection implements _Event {
+  const _UpdateCollection(this.collection);
+
+  @override
+  String toString() => _$toString();
+
+  final Collection collection;
+}
+
+@toString
+class _LoadSharee implements _Event {
+  const _LoadSharee();
+
+  @override
+  String toString() => _$toString();
+}
+
+@toString
+class _RefreshSuggester implements _Event {
+  const _RefreshSuggester();
+
+  @override
+  String toString() => _$toString();
+}
+
+mixin _ShareEventTag implements _Event {}
+
+@toString
+class _Share with _ShareEventTag implements _Event {
+  const _Share(this.sharee);
+
+  @override
+  String toString() => _$toString();
+
+  final Sharee sharee;
+}
+
+@toString
+class _Unshare with _ShareEventTag implements _Event {
+  const _Unshare(this.share);
+
+  @override
+  String toString() => _$toString();
+
+  final CollectionShare share;
+}
+
+@toString
+class _SetError implements _Event {
+  const _SetError(this.error, [this.stackTrace]);
+
+  @override
+  String toString() => _$toString();
+
+  final Object error;
+  final StackTrace? stackTrace;
+}
diff --git a/app/test/use_case/share_album_with_user_test.dart b/app/test/use_case/share_album_with_user_test.dart
index e829689a..b313e836 100644
--- a/app/test/use_case/share_album_with_user_test.dart
+++ b/app/test/use_case/share_album_with_user_test.dart
@@ -1,7 +1,7 @@
 import 'package:event_bus/event_bus.dart';
 import 'package:kiwi/kiwi.dart';
 import 'package:nc_photos/or_null.dart';
-import 'package:nc_photos/use_case/share_album_with_user.dart';
+import 'package:nc_photos/use_case/album/share_album_with_user.dart';
 import 'package:np_common/ci_string.dart';
 import 'package:test/test.dart';
 
diff --git a/app/test/use_case/unshare_album_with_user_test.dart b/app/test/use_case/unshare_album_with_user_test.dart
index 00cd6a55..59e6cf5d 100644
--- a/app/test/use_case/unshare_album_with_user_test.dart
+++ b/app/test/use_case/unshare_album_with_user_test.dart
@@ -1,7 +1,7 @@
 import 'package:event_bus/event_bus.dart';
 import 'package:kiwi/kiwi.dart';
 import 'package:nc_photos/di_container.dart';
-import 'package:nc_photos/use_case/unshare_album_with_user.dart';
+import 'package:nc_photos/use_case/album/unshare_album_with_user.dart';
 import 'package:np_common/ci_string.dart';
 import 'package:test/test.dart';