diff --git a/packages/stream_feeds/CHANGELOG.md b/packages/stream_feeds/CHANGELOG.md
index 390dd538..4adbe7d7 100644
--- a/packages/stream_feeds/CHANGELOG.md
+++ b/packages/stream_feeds/CHANGELOG.md
@@ -3,6 +3,9 @@
 - [BREAKING] Renamed `ActivitiesFilterField.type` to `ActivitiesFilterField.activityType`.
 - [BREAKING] Changed `ActivityData.location` field type from `ActivityLocation?` to `LocationCoordinate?`.
 - Add support for `enforceUnique` parameter while adding reactions.
+- [BREAKING] Changed default behavior for `ActivityAddedEvent` in feeds: activities from other users
+  are now ignored by default. Only activities from the current user matching the feed's filter are
+  added. Add `onNewActivity` callback to `feed`, `feedFromId`, or `feedFromQuery` to customize.
 - Add location filtering support for activities with `ActivitiesFilterField.near` and `ActivitiesFilterField.withinBounds` filter fields.
 - Add new activity filter fields: `ActivitiesFilterField.feed` and `ActivitiesFilterField.interestTags`.
 
diff --git a/packages/stream_feeds/lib/src/client/feeds_client_impl.dart b/packages/stream_feeds/lib/src/client/feeds_client_impl.dart
index d4aad511..95fe2ca5 100644
--- a/packages/stream_feeds/lib/src/client/feeds_client_impl.dart
+++ b/packages/stream_feeds/lib/src/client/feeds_client_impl.dart
@@ -31,6 +31,7 @@ import '../state/bookmark_list.dart';
 import '../state/comment_list.dart';
 import '../state/comment_reaction_list.dart';
 import '../state/comment_reply_list.dart';
+import '../state/event/on_activity_added.dart';
 import '../state/feed.dart';
 import '../state/feed_list.dart';
 import '../state/follow_list.dart';
@@ -267,10 +268,14 @@ class StreamFeedsClientImpl implements StreamFeedsClient {
   }
 
   @override
-  Feed feedFromQuery(FeedQuery query) {
+  Feed feedFromQuery(
+    FeedQuery query, {
+    OnNewActivity onNewActivity = defaultOnNewActivity,
+  }) {
     return Feed(
       query: query,
       currentUserId: user.id,
+      onNewActivity: onNewActivity,
       activitiesRepository: _activitiesRepository,
       bookmarksRepository: _bookmarksRepository,
       commentsRepository: _commentsRepository,
diff --git a/packages/stream_feeds/lib/src/feeds_client.dart b/packages/stream_feeds/lib/src/feeds_client.dart
index a46cbf1b..814e28a0 100644
--- a/packages/stream_feeds/lib/src/feeds_client.dart
+++ b/packages/stream_feeds/lib/src/feeds_client.dart
@@ -18,6 +18,7 @@ import 'state/bookmark_list.dart';
 import 'state/comment_list.dart';
 import 'state/comment_reaction_list.dart';
 import 'state/comment_reply_list.dart';
+import 'state/event/on_activity_added.dart';
 import 'state/feed.dart';
 import 'state/feed_list.dart';
 import 'state/follow_list.dart';
@@ -223,6 +224,11 @@ abstract interface class StreamFeedsClient {
   /// Creates a [Feed] object using a [FeedQuery] that can include additional
   /// configuration such as activity filters, limits, and feed data for creation.
   ///
+  /// When [onNewActivity] is provided, it customizes how new activities received
+  /// via real-time events are inserted into the feed. When null, uses the default
+  /// behavior which adds activities created by the current user to the start of
+  /// the feed if they match the feed's filter.
+  ///
   /// Example:
   /// ```dart
   /// final feed = client.feedFromQuery(FeedQuery(
@@ -236,7 +242,10 @@ abstract interface class StreamFeedsClient {
   /// ```
   ///
   /// Returns a [Feed] instance that can be used to interact with the specified feed.
-  Feed feedFromQuery(FeedQuery query);
+  Feed feedFromQuery(
+    FeedQuery query, {
+    OnNewActivity onNewActivity,
+  });
 
   /// Creates a feed list instance based on the provided [query].
   ///
@@ -764,6 +773,11 @@ extension StreamFeedsClientHelpers on StreamFeedsClient {
   /// Creates a [Feed] object that represents a specific feed.
   /// The feed can be used to fetch activities, manage follows, and receive real-time updates.
   ///
+  /// When [onNewActivity] is provided, it customizes how new activities received
+  /// via real-time events are inserted into the feed. Defaults to [defaultOnNewActivity],
+  /// which adds activities created by the current user to the start of the feed
+  /// if they match the feed's filter.
+  ///
   /// Example:
   /// ```dart
   /// final userFeed = client.feed('user', 'john');
@@ -783,9 +797,13 @@ extension StreamFeedsClientHelpers on StreamFeedsClient {
   /// ```
   ///
   /// Returns a [Feed] instance that can be used to interact with the specified feed.
-  Feed feed({required String group, required String id}) {
+  Feed feed({
+    required String group,
+    required String id,
+    OnNewActivity onNewActivity = defaultOnNewActivity,
+  }) {
     final fid = FeedId(group: group, id: id);
-    return feedFromId(fid);
+    return feedFromId(fid, onNewActivity: onNewActivity);
   }
 
   /// Creates a feed instance for the specified [fid].
@@ -793,6 +811,11 @@ extension StreamFeedsClientHelpers on StreamFeedsClient {
   /// Creates a [Feed] object that represents a specific feed.
   /// The feed can be used to fetch activities, manage follows, and receive real-time updates.
   ///
+  /// When [onNewActivity] is provided, it customizes how new activities received
+  /// via real-time events are inserted into the feed. Defaults to [defaultOnNewActivity],
+  /// which adds activities created by the current user to the start of the feed
+  /// if they match the feed's filter.
+  ///
   /// Example:
   /// ```dart
   /// final feedId = FeedId(group: 'user', id: 'john');
@@ -802,8 +825,11 @@ extension StreamFeedsClientHelpers on StreamFeedsClient {
   /// ```
   ///
   /// Returns a [Feed] instance that can be used to interact with the specified feed.
-  Feed feedFromId(FeedId fid) {
+  Feed feedFromId(
+    FeedId fid, {
+    OnNewActivity onNewActivity = defaultOnNewActivity,
+  }) {
     final query = FeedQuery(fid: fid);
-    return feedFromQuery(query);
+    return feedFromQuery(query, onNewActivity: onNewActivity);
   }
 }
diff --git a/packages/stream_feeds/lib/src/state.dart b/packages/stream_feeds/lib/src/state.dart
index 9074d554..c5dec18a 100644
--- a/packages/stream_feeds/lib/src/state.dart
+++ b/packages/stream_feeds/lib/src/state.dart
@@ -20,6 +20,7 @@ export 'state/feed_list_state.dart';
 export 'state/feed_state.dart';
 export 'state/follow_list.dart';
 export 'state/follow_list_state.dart';
+export 'state/insertion_action.dart';
 export 'state/poll_list.dart';
 export 'state/poll_list_state.dart';
 export 'state/poll_vote_list.dart';
diff --git a/packages/stream_feeds/lib/src/state/activity.dart b/packages/stream_feeds/lib/src/state/activity.dart
index 6aaf2983..be2ab8ad 100644
--- a/packages/stream_feeds/lib/src/state/activity.dart
+++ b/packages/stream_feeds/lib/src/state/activity.dart
@@ -20,7 +20,7 @@ import '../repository/comments_repository.dart';
 import '../repository/polls_repository.dart';
 import 'activity_comment_list.dart';
 import 'activity_state.dart';
-import 'event/activity_event_handler.dart';
+import 'event/handler/activity_event_handler.dart';
 import 'query/activity_comments_query.dart';
 import 'state_notifier_extentions.dart';
 
diff --git a/packages/stream_feeds/lib/src/state/activity_comment_list.dart b/packages/stream_feeds/lib/src/state/activity_comment_list.dart
index bf7bfa41..4641e259 100644
--- a/packages/stream_feeds/lib/src/state/activity_comment_list.dart
+++ b/packages/stream_feeds/lib/src/state/activity_comment_list.dart
@@ -7,7 +7,7 @@ import 'package:stream_core/stream_core.dart';
 import '../models/comment_data.dart';
 import '../repository/comments_repository.dart';
 import 'activity_comment_list_state.dart';
-import 'event/activity_comment_list_event_handler.dart';
+import 'event/handler/activity_comment_list_event_handler.dart';
 import 'query/activity_comments_query.dart';
 import 'state_notifier_extentions.dart';
 
diff --git a/packages/stream_feeds/lib/src/state/activity_list.dart b/packages/stream_feeds/lib/src/state/activity_list.dart
index 301f075a..dbe5983d 100644
--- a/packages/stream_feeds/lib/src/state/activity_list.dart
+++ b/packages/stream_feeds/lib/src/state/activity_list.dart
@@ -9,7 +9,7 @@ import '../models/query_configuration.dart';
 import '../repository/activities_repository.dart';
 import '../repository/capabilities_repository.dart';
 import 'activity_list_state.dart';
-import 'event/activity_list_event_handler.dart';
+import 'event/handler/activity_list_event_handler.dart';
 import 'query/activities_query.dart';
 import 'state_notifier_extentions.dart';
 
diff --git a/packages/stream_feeds/lib/src/state/activity_reaction_list.dart b/packages/stream_feeds/lib/src/state/activity_reaction_list.dart
index 500fdda9..0be74052 100644
--- a/packages/stream_feeds/lib/src/state/activity_reaction_list.dart
+++ b/packages/stream_feeds/lib/src/state/activity_reaction_list.dart
@@ -8,7 +8,7 @@ import '../models/feeds_reaction_data.dart';
 import '../models/query_configuration.dart';
 import '../repository/activities_repository.dart';
 import 'activity_reaction_list_state.dart';
-import 'event/activity_reaction_list_event_handler.dart';
+import 'event/handler/activity_reaction_list_event_handler.dart';
 import 'query/activity_reactions_query.dart';
 import 'state_notifier_extentions.dart';
 
diff --git a/packages/stream_feeds/lib/src/state/bookmark_folder_list.dart b/packages/stream_feeds/lib/src/state/bookmark_folder_list.dart
index 7e976831..7198b9f2 100644
--- a/packages/stream_feeds/lib/src/state/bookmark_folder_list.dart
+++ b/packages/stream_feeds/lib/src/state/bookmark_folder_list.dart
@@ -8,7 +8,7 @@ import '../models/bookmark_folder_data.dart';
 import '../models/query_configuration.dart';
 import '../repository/bookmarks_repository.dart';
 import 'bookmark_folder_list_state.dart';
-import 'event/bookmark_folder_list_event_handler.dart';
+import 'event/handler/bookmark_folder_list_event_handler.dart';
 import 'query/bookmark_folders_query.dart';
 import 'state_notifier_extentions.dart';
 
diff --git a/packages/stream_feeds/lib/src/state/bookmark_list.dart b/packages/stream_feeds/lib/src/state/bookmark_list.dart
index 617f471a..39d2fb83 100644
--- a/packages/stream_feeds/lib/src/state/bookmark_list.dart
+++ b/packages/stream_feeds/lib/src/state/bookmark_list.dart
@@ -8,7 +8,7 @@ import '../models/bookmark_data.dart';
 import '../models/query_configuration.dart';
 import '../repository/bookmarks_repository.dart';
 import 'bookmark_list_state.dart';
-import 'event/bookmark_list_event_handler.dart';
+import 'event/handler/bookmark_list_event_handler.dart';
 import 'query/bookmarks_query.dart';
 import 'state_notifier_extentions.dart';
 
diff --git a/packages/stream_feeds/lib/src/state/comment_list.dart b/packages/stream_feeds/lib/src/state/comment_list.dart
index da07af0a..d3946cd5 100644
--- a/packages/stream_feeds/lib/src/state/comment_list.dart
+++ b/packages/stream_feeds/lib/src/state/comment_list.dart
@@ -7,7 +7,7 @@ import 'package:stream_core/stream_core.dart';
 import '../models/comment_data.dart';
 import '../repository/comments_repository.dart';
 import 'comment_list_state.dart';
-import 'event/comment_list_event_handler.dart';
+import 'event/handler/comment_list_event_handler.dart';
 import 'query/comments_query.dart';
 import 'state_notifier_extentions.dart';
 
diff --git a/packages/stream_feeds/lib/src/state/comment_reaction_list.dart b/packages/stream_feeds/lib/src/state/comment_reaction_list.dart
index 7e4249e7..59b868fa 100644
--- a/packages/stream_feeds/lib/src/state/comment_reaction_list.dart
+++ b/packages/stream_feeds/lib/src/state/comment_reaction_list.dart
@@ -8,7 +8,7 @@ import '../models/feeds_reaction_data.dart';
 import '../models/query_configuration.dart';
 import '../repository/comments_repository.dart';
 import 'comment_reaction_list_state.dart';
-import 'event/comment_reaction_list_event_handler.dart';
+import 'event/handler/comment_reaction_list_event_handler.dart';
 import 'query/comment_reactions_query.dart';
 import 'state_notifier_extentions.dart';
 
diff --git a/packages/stream_feeds/lib/src/state/comment_reply_list.dart b/packages/stream_feeds/lib/src/state/comment_reply_list.dart
index f56c2f94..036cf0f3 100644
--- a/packages/stream_feeds/lib/src/state/comment_reply_list.dart
+++ b/packages/stream_feeds/lib/src/state/comment_reply_list.dart
@@ -7,7 +7,7 @@ import 'package:stream_core/stream_core.dart';
 import '../models/comment_data.dart';
 import '../repository/comments_repository.dart';
 import 'comment_reply_list_state.dart';
-import 'event/comment_reply_list_event_handler.dart';
+import 'event/handler/comment_reply_list_event_handler.dart';
 import 'query/comment_replies_query.dart';
 import 'state_notifier_extentions.dart';
 
diff --git a/packages/stream_feeds/lib/src/state/event/activity_comment_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/activity_comment_list_event_handler.dart
similarity index 93%
rename from packages/stream_feeds/lib/src/state/event/activity_comment_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/activity_comment_list_event_handler.dart
index 9384821b..c0bc07ac 100644
--- a/packages/stream_feeds/lib/src/state/event/activity_comment_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/activity_comment_list_event_handler.dart
@@ -1,9 +1,9 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/comment_data.dart';
-import '../../models/feeds_reaction_data.dart';
-import '../activity_comment_list_state.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/comment_data.dart';
+import '../../../models/feeds_reaction_data.dart';
+import '../../activity_comment_list_state.dart';
 import 'state_event_handler.dart';
 
 /// Event handler for activity comment list real-time updates.
diff --git a/packages/stream_feeds/lib/src/state/event/activity_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/activity_event_handler.dart
similarity index 88%
rename from packages/stream_feeds/lib/src/state/event/activity_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/activity_event_handler.dart
index 0895daad..72c45d8d 100644
--- a/packages/stream_feeds/lib/src/state/event/activity_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/activity_event_handler.dart
@@ -1,12 +1,12 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/feed_id.dart';
-import '../../models/poll_data.dart';
-import '../../models/poll_vote_data.dart';
-import '../../resolvers/poll/poll_answer_casted.dart';
-import '../../resolvers/poll/poll_answer_removed.dart';
-import '../activity_state.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/feed_id.dart';
+import '../../../models/poll_data.dart';
+import '../../../models/poll_vote_data.dart';
+import '../../../resolvers/poll/poll_answer_casted.dart';
+import '../../../resolvers/poll/poll_answer_removed.dart';
+import '../../activity_state.dart';
 import 'state_event_handler.dart';
 
 /// Event handler for activity real-time updates.
diff --git a/packages/stream_feeds/lib/src/state/event/activity_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/activity_list_event_handler.dart
similarity index 93%
rename from packages/stream_feeds/lib/src/state/event/activity_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/activity_list_event_handler.dart
index 7438fe0a..97f02a2d 100644
--- a/packages/stream_feeds/lib/src/state/event/activity_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/activity_list_event_handler.dart
@@ -1,13 +1,13 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/activity_data.dart';
-import '../../models/bookmark_data.dart';
-import '../../models/comment_data.dart';
-import '../../models/feeds_reaction_data.dart';
-import '../../repository/capabilities_repository.dart';
-import '../activity_list_state.dart';
-import '../query/activities_query.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/activity_data.dart';
+import '../../../models/bookmark_data.dart';
+import '../../../models/comment_data.dart';
+import '../../../models/feeds_reaction_data.dart';
+import '../../../repository/capabilities_repository.dart';
+import '../../activity_list_state.dart';
+import '../../query/activities_query.dart';
 import 'feed_capabilities_mixin.dart';
 import 'state_event_handler.dart';
 
diff --git a/packages/stream_feeds/lib/src/state/event/activity_reaction_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/activity_reaction_list_event_handler.dart
similarity index 85%
rename from packages/stream_feeds/lib/src/state/event/activity_reaction_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/activity_reaction_list_event_handler.dart
index 2be9b8c5..82de4482 100644
--- a/packages/stream_feeds/lib/src/state/event/activity_reaction_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/activity_reaction_list_event_handler.dart
@@ -1,8 +1,8 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/feeds_reaction_data.dart';
-import '../activity_reaction_list_state.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/feeds_reaction_data.dart';
+import '../../activity_reaction_list_state.dart';
 import 'state_event_handler.dart';
 
 /// Event handler for activity reaction list real-time updates.
diff --git a/packages/stream_feeds/lib/src/state/event/bookmark_folder_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/bookmark_folder_list_event_handler.dart
similarity index 86%
rename from packages/stream_feeds/lib/src/state/event/bookmark_folder_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/bookmark_folder_list_event_handler.dart
index 586852f9..ed2d6b63 100644
--- a/packages/stream_feeds/lib/src/state/event/bookmark_folder_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/bookmark_folder_list_event_handler.dart
@@ -1,9 +1,9 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/bookmark_folder_data.dart';
-import '../bookmark_folder_list_state.dart';
-import '../query/bookmark_folders_query.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/bookmark_folder_data.dart';
+import '../../bookmark_folder_list_state.dart';
+import '../../query/bookmark_folders_query.dart';
 import 'state_event_handler.dart';
 
 /// Event handler for bookmark folder list real-time updates.
diff --git a/packages/stream_feeds/lib/src/state/event/bookmark_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/bookmark_list_event_handler.dart
similarity index 85%
rename from packages/stream_feeds/lib/src/state/event/bookmark_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/bookmark_list_event_handler.dart
index 6b98e1d7..1e3d0c07 100644
--- a/packages/stream_feeds/lib/src/state/event/bookmark_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/bookmark_list_event_handler.dart
@@ -1,10 +1,10 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/bookmark_data.dart';
-import '../../models/bookmark_folder_data.dart';
-import '../bookmark_list_state.dart';
-import '../query/bookmarks_query.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/bookmark_data.dart';
+import '../../../models/bookmark_folder_data.dart';
+import '../../bookmark_list_state.dart';
+import '../../query/bookmarks_query.dart';
 import 'state_event_handler.dart';
 
 /// Event handler for bookmark list real-time updates.
diff --git a/packages/stream_feeds/lib/src/state/event/comment_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/comment_list_event_handler.dart
similarity index 86%
rename from packages/stream_feeds/lib/src/state/event/comment_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/comment_list_event_handler.dart
index 9f4d4062..c83864f6 100644
--- a/packages/stream_feeds/lib/src/state/event/comment_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/comment_list_event_handler.dart
@@ -1,10 +1,10 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
+import '../../../generated/api/models.dart' as api;
 
-import '../../models/comment_data.dart';
-import '../comment_list_state.dart';
-import '../query/comments_query.dart';
+import '../../../models/comment_data.dart';
+import '../../comment_list_state.dart';
+import '../../query/comments_query.dart';
 import 'state_event_handler.dart';
 
 /// Event handler for comment list real-time updates.
diff --git a/packages/stream_feeds/lib/src/state/event/comment_reaction_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/comment_reaction_list_event_handler.dart
similarity index 82%
rename from packages/stream_feeds/lib/src/state/event/comment_reaction_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/comment_reaction_list_event_handler.dart
index 3f2bd685..6f268d85 100644
--- a/packages/stream_feeds/lib/src/state/event/comment_reaction_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/comment_reaction_list_event_handler.dart
@@ -1,8 +1,8 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/feeds_reaction_data.dart';
-import '../comment_reaction_list_state.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/feeds_reaction_data.dart';
+import '../../comment_reaction_list_state.dart';
 import 'state_event_handler.dart';
 
 /// Event handler for comment reaction list real-time updates.
diff --git a/packages/stream_feeds/lib/src/state/event/comment_reply_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/comment_reply_list_event_handler.dart
similarity index 90%
rename from packages/stream_feeds/lib/src/state/event/comment_reply_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/comment_reply_list_event_handler.dart
index 1841bbf1..fb2175cf 100644
--- a/packages/stream_feeds/lib/src/state/event/comment_reply_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/comment_reply_list_event_handler.dart
@@ -1,9 +1,9 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/comment_data.dart';
-import '../../models/feeds_reaction_data.dart';
-import '../comment_reply_list_state.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/comment_data.dart';
+import '../../../models/feeds_reaction_data.dart';
+import '../../comment_reply_list_state.dart';
 import 'state_event_handler.dart';
 
 /// Event handler for comment reply list real-time updates.
diff --git a/packages/stream_feeds/lib/src/state/event/feed_capabilities_mixin.dart b/packages/stream_feeds/lib/src/state/event/handler/feed_capabilities_mixin.dart
similarity index 82%
rename from packages/stream_feeds/lib/src/state/event/feed_capabilities_mixin.dart
rename to packages/stream_feeds/lib/src/state/event/handler/feed_capabilities_mixin.dart
index 11a6aeeb..55e63047 100644
--- a/packages/stream_feeds/lib/src/state/event/feed_capabilities_mixin.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/feed_capabilities_mixin.dart
@@ -1,5 +1,5 @@
-import '../../../stream_feeds.dart';
-import '../../repository/capabilities_repository.dart';
+import '../../../../stream_feeds.dart';
+import '../../../repository/capabilities_repository.dart';
 
 mixin FeedCapabilitiesMixin {
   CapabilitiesRepository get capabilitiesRepository;
diff --git a/packages/stream_feeds/lib/src/state/event/feed_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/feed_event_handler.dart
similarity index 89%
rename from packages/stream_feeds/lib/src/state/event/feed_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/feed_event_handler.dart
index dea127da..f74c259d 100644
--- a/packages/stream_feeds/lib/src/state/event/feed_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/feed_event_handler.dart
@@ -1,19 +1,20 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/activity_data.dart';
-import '../../models/activity_pin_data.dart';
-import '../../models/aggregated_activity_data.dart';
-import '../../models/bookmark_data.dart';
-import '../../models/comment_data.dart';
-import '../../models/feed_data.dart';
-import '../../models/feeds_reaction_data.dart';
-import '../../models/follow_data.dart';
-import '../../models/mark_activity_data.dart';
-import '../../repository/capabilities_repository.dart';
-import '../feed_state.dart';
-
-import '../query/feed_query.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/activity_data.dart';
+import '../../../models/activity_pin_data.dart';
+import '../../../models/aggregated_activity_data.dart';
+import '../../../models/bookmark_data.dart';
+import '../../../models/comment_data.dart';
+import '../../../models/feed_data.dart';
+import '../../../models/feeds_reaction_data.dart';
+import '../../../models/follow_data.dart';
+import '../../../models/mark_activity_data.dart';
+import '../../../repository/capabilities_repository.dart';
+import '../../feed_state.dart';
+
+import '../../query/feed_query.dart';
+import '../on_activity_added.dart';
 import 'feed_capabilities_mixin.dart';
 import 'state_event_handler.dart';
 
@@ -22,12 +23,14 @@ class FeedEventHandler with FeedCapabilitiesMixin implements StateEventHandler {
     required this.query,
     required this.state,
     required this.currentUserId,
+    required this.onNewActivity,
     required this.capabilitiesRepository,
   });
 
   final FeedQuery query;
-  final FeedStateNotifier state;
   final String currentUserId;
+  final FeedStateNotifier state;
+  final OnNewActivity onNewActivity;
 
   @override
   final CapabilitiesRepository capabilitiesRepository;
@@ -44,11 +47,10 @@ class FeedEventHandler with FeedCapabilitiesMixin implements StateEventHandler {
 
     if (event is api.ActivityAddedEvent) {
       if (event.fid != fid.rawValue) return;
-
       final activity = event.activity.toModel();
-      if (!matchesQueryFilter(activity)) return;
 
-      state.onActivityAdded(activity);
+      final insertionAction = onNewActivity(query, activity, currentUserId);
+      state.onActivityAdded(activity, insertionAction: insertionAction);
 
       final updatedActivity = await withUpdatedFeedCapabilities(activity);
       if (updatedActivity != null) state.onActivityUpdated(updatedActivity);
diff --git a/packages/stream_feeds/lib/src/state/event/feed_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/feed_list_event_handler.dart
similarity index 83%
rename from packages/stream_feeds/lib/src/state/event/feed_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/feed_list_event_handler.dart
index 3ae32761..c106e1a8 100644
--- a/packages/stream_feeds/lib/src/state/event/feed_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/feed_list_event_handler.dart
@@ -1,10 +1,10 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/feed_data.dart';
-import '../feed_list_state.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/feed_data.dart';
+import '../../feed_list_state.dart';
 
-import '../query/feeds_query.dart';
+import '../../query/feeds_query.dart';
 import 'state_event_handler.dart';
 
 class FeedListEventHandler implements StateEventHandler {
diff --git a/packages/stream_feeds/lib/src/state/event/follow_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/follow_list_event_handler.dart
similarity index 85%
rename from packages/stream_feeds/lib/src/state/event/follow_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/follow_list_event_handler.dart
index 2833a2da..a240a052 100644
--- a/packages/stream_feeds/lib/src/state/event/follow_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/follow_list_event_handler.dart
@@ -1,9 +1,9 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/follow_data.dart';
-import '../follow_list_state.dart';
-import '../query/follows_query.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/follow_data.dart';
+import '../../follow_list_state.dart';
+import '../../query/follows_query.dart';
 import 'state_event_handler.dart';
 
 /// Event handler for follow list real-time updates.
diff --git a/packages/stream_feeds/lib/src/state/event/member_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/member_list_event_handler.dart
similarity index 85%
rename from packages/stream_feeds/lib/src/state/event/member_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/member_list_event_handler.dart
index 09b15b36..4eae1a6f 100644
--- a/packages/stream_feeds/lib/src/state/event/member_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/member_list_event_handler.dart
@@ -1,10 +1,10 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/feed_member_data.dart';
-import '../member_list_state.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/feed_member_data.dart';
+import '../../member_list_state.dart';
 
-import '../query/members_query.dart';
+import '../../query/members_query.dart';
 import 'state_event_handler.dart';
 
 class MemberListEventHandler implements StateEventHandler {
diff --git a/packages/stream_feeds/lib/src/state/event/poll_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/poll_list_event_handler.dart
similarity index 85%
rename from packages/stream_feeds/lib/src/state/event/poll_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/poll_list_event_handler.dart
index b4e0a948..8a9b287f 100644
--- a/packages/stream_feeds/lib/src/state/event/poll_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/poll_list_event_handler.dart
@@ -1,9 +1,9 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/poll_data.dart';
-import '../poll_list_state.dart';
-import '../query/polls_query.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/poll_data.dart';
+import '../../poll_list_state.dart';
+import '../../query/polls_query.dart';
 import 'state_event_handler.dart';
 
 /// Event handler for poll list real-time updates.
diff --git a/packages/stream_feeds/lib/src/state/event/poll_vote_list_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/poll_vote_list_event_handler.dart
similarity index 88%
rename from packages/stream_feeds/lib/src/state/event/poll_vote_list_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/poll_vote_list_event_handler.dart
index 69f24f4f..97f3916b 100644
--- a/packages/stream_feeds/lib/src/state/event/poll_vote_list_event_handler.dart
+++ b/packages/stream_feeds/lib/src/state/event/handler/poll_vote_list_event_handler.dart
@@ -1,9 +1,9 @@
 import 'package:stream_core/stream_core.dart';
 
-import '../../generated/api/models.dart' as api;
-import '../../models/poll_vote_data.dart';
-import '../poll_vote_list_state.dart';
-import '../query/poll_votes_query.dart';
+import '../../../generated/api/models.dart' as api;
+import '../../../models/poll_vote_data.dart';
+import '../../poll_vote_list_state.dart';
+import '../../query/poll_votes_query.dart';
 import 'state_event_handler.dart';
 
 /// Event handler for poll vote list real-time updates.
diff --git a/packages/stream_feeds/lib/src/state/event/state_event_handler.dart b/packages/stream_feeds/lib/src/state/event/handler/state_event_handler.dart
similarity index 100%
rename from packages/stream_feeds/lib/src/state/event/state_event_handler.dart
rename to packages/stream_feeds/lib/src/state/event/handler/state_event_handler.dart
diff --git a/packages/stream_feeds/lib/src/state/event/on_activity_added.dart b/packages/stream_feeds/lib/src/state/event/on_activity_added.dart
new file mode 100644
index 00000000..e2fe0c69
--- /dev/null
+++ b/packages/stream_feeds/lib/src/state/event/on_activity_added.dart
@@ -0,0 +1,71 @@
+import 'package:meta/meta.dart';
+
+import '../../models/activity_data.dart';
+import '../../utils/filter.dart';
+import '../insertion_action.dart';
+import '../query/feed_query.dart';
+
+/// A callback function that determines how to handle a new activity.
+///
+/// This optional callback can be provided to customize insertion behavior when
+/// new activities are received. It allows determining how activities should be
+/// inserted based on the activity, query, and current user context.
+///
+/// The function receives:
+/// - [query]: The query that defines the filter and configuration
+/// - [activity]: The newly added activity
+/// - [currentUserId]: The ID of the current user
+///
+/// Returns an [InsertionAction] that determines how the activity should be
+/// inserted into the activity list:
+/// - [InsertionAction.addToStart]: Add the activity at the beginning of the list
+/// - [InsertionAction.addToEnd]: Add the activity at the end of the list
+/// - [InsertionAction.ignore]: Do not add the activity to the list
+///
+/// ## Example
+/// ```dart
+/// // Custom handler that adds all activities from followed users to the start
+/// InsertionAction customOnNewActivity(
+///   FeedQuery query,
+///   ActivityData activity,
+///   String currentUserId,
+/// ) {
+///   // Add activities from followed users to the start
+///   if (activity.user.id != currentUserId) {
+///     return InsertionAction.addToStart;
+///   }
+///   return InsertionAction.ignore;
+/// }
+///
+/// final feed = client.feed(
+///   group: 'user',
+///   id: 'john',
+///   onNewActivity: customOnNewActivity,
+/// );
+/// ```
+typedef OnNewActivity = InsertionAction Function(
+  FeedQuery query,
+  ActivityData activity,
+  String currentUserId,
+);
+
+/// Default handler for new activities.
+///
+/// Adds activities created by the current user to the start of the list if they
+/// match the query's filter. Ignores all other activities.
+@internal
+InsertionAction defaultOnNewActivity(
+  FeedQuery query,
+  ActivityData activity,
+  String currentUserId,
+) {
+  // If the activity was created by the current user and matches the filter,
+  // add it to the start of the list; otherwise, ignore it.
+  if (activity.user.id == currentUserId) {
+    if (activity.matches(query.activityFilter)) {
+      return InsertionAction.addToStart;
+    }
+  }
+
+  return InsertionAction.ignore;
+}
diff --git a/packages/stream_feeds/lib/src/state/feed.dart b/packages/stream_feeds/lib/src/state/feed.dart
index 57094000..78e9e3dc 100644
--- a/packages/stream_feeds/lib/src/state/feed.dart
+++ b/packages/stream_feeds/lib/src/state/feed.dart
@@ -24,7 +24,8 @@ import '../repository/capabilities_repository.dart';
 import '../repository/comments_repository.dart';
 import '../repository/feeds_repository.dart';
 import '../repository/polls_repository.dart';
-import 'event/feed_event_handler.dart';
+import 'event/handler/feed_event_handler.dart';
+import 'event/on_activity_added.dart';
 import 'feed_state.dart';
 import 'member_list.dart';
 import 'query/feed_query.dart';
@@ -45,6 +46,7 @@ class Feed with Disposable {
   Feed({
     required this.query,
     required this.currentUserId,
+    required this.onNewActivity,
     required this.activitiesRepository,
     required this.bookmarksRepository,
     required this.commentsRepository,
@@ -73,6 +75,7 @@ class Feed with Disposable {
       query: query,
       state: _stateNotifier,
       currentUserId: currentUserId,
+      onNewActivity: onNewActivity,
       capabilitiesRepository: capabilitiesRepository,
     );
 
@@ -88,6 +91,7 @@ class Feed with Disposable {
   final FeedQuery query;
   final String currentUserId;
 
+  final OnNewActivity onNewActivity;
   final ActivitiesRepository activitiesRepository;
   final BookmarksRepository bookmarksRepository;
   final CommentsRepository commentsRepository;
diff --git a/packages/stream_feeds/lib/src/state/feed_list.dart b/packages/stream_feeds/lib/src/state/feed_list.dart
index d82ae893..3be3f455 100644
--- a/packages/stream_feeds/lib/src/state/feed_list.dart
+++ b/packages/stream_feeds/lib/src/state/feed_list.dart
@@ -7,7 +7,7 @@ import 'package:stream_core/stream_core.dart';
 import '../models/feed_data.dart';
 import '../models/query_configuration.dart';
 import '../repository/feeds_repository.dart';
-import 'event/feed_list_event_handler.dart';
+import 'event/handler/feed_list_event_handler.dart';
 import 'feed_list_state.dart';
 import 'query/feeds_query.dart';
 import 'state_notifier_extentions.dart';
diff --git a/packages/stream_feeds/lib/src/state/feed_state.dart b/packages/stream_feeds/lib/src/state/feed_state.dart
index 816b26ee..3d26d131 100644
--- a/packages/stream_feeds/lib/src/state/feed_state.dart
+++ b/packages/stream_feeds/lib/src/state/feed_state.dart
@@ -20,6 +20,7 @@ import '../models/get_or_create_feed_data.dart';
 import '../models/mark_activity_data.dart';
 import '../models/pagination_data.dart';
 import '../models/query_configuration.dart';
+import 'insertion_action.dart';
 import 'member_list_state.dart';
 import 'query/activities_query.dart';
 import 'query/feed_query.dart';
@@ -108,12 +109,24 @@ class FeedStateNotifier extends StateNotifier<FeedState> {
   }
 
   /// Handles updates to the feed state when a new activity is added.
-  void onActivityAdded(ActivityData activity) {
+  void onActivityAdded(
+    ActivityData activity, {
+    InsertionAction insertionAction = InsertionAction.addToStart,
+  }) {
+    final insertAt = switch (insertionAction) {
+      InsertionAction.addToStart => 0,
+      InsertionAction.addToEnd => state.activities.length,
+      InsertionAction.ignore => null,
+    };
+
+    // Return early if the activity should be ignored
+    if (insertAt == null) return;
+
     // Upsert the new activity into the existing activities list
-    final updatedActivities = state.activities.sortedUpsert(
+    final updatedActivities = state.activities.upsert(
       activity,
       key: (it) => it.id,
-      compare: activitiesSort.compare,
+      insertAt: (_) => insertAt,
     );
 
     state = state.copyWith(activities: updatedActivities);
diff --git a/packages/stream_feeds/lib/src/state/follow_list.dart b/packages/stream_feeds/lib/src/state/follow_list.dart
index 2bc4db05..a6f7e632 100644
--- a/packages/stream_feeds/lib/src/state/follow_list.dart
+++ b/packages/stream_feeds/lib/src/state/follow_list.dart
@@ -7,7 +7,7 @@ import 'package:stream_core/stream_core.dart';
 import '../models/follow_data.dart';
 import '../models/query_configuration.dart';
 import '../repository/feeds_repository.dart';
-import 'event/follow_list_event_handler.dart';
+import 'event/handler/follow_list_event_handler.dart';
 import 'follow_list_state.dart';
 import 'query/follows_query.dart';
 import 'state_notifier_extentions.dart';
diff --git a/packages/stream_feeds/lib/src/state/insertion_action.dart b/packages/stream_feeds/lib/src/state/insertion_action.dart
new file mode 100644
index 00000000..ccf26978
--- /dev/null
+++ b/packages/stream_feeds/lib/src/state/insertion_action.dart
@@ -0,0 +1,13 @@
+/// Defines how an item should be inserted into a list.
+///
+/// Used to specify the insertion position when adding new items to collections.
+enum InsertionAction {
+  /// Do not add the item to the list.
+  ignore,
+
+  /// Add the item at the end of the list.
+  addToEnd,
+
+  /// Add the item at the beginning of the list.
+  addToStart,
+}
diff --git a/packages/stream_feeds/lib/src/state/member_list.dart b/packages/stream_feeds/lib/src/state/member_list.dart
index fad23469..388b17c1 100644
--- a/packages/stream_feeds/lib/src/state/member_list.dart
+++ b/packages/stream_feeds/lib/src/state/member_list.dart
@@ -7,7 +7,7 @@ import 'package:stream_core/stream_core.dart';
 import '../models/feed_member_data.dart';
 import '../models/query_configuration.dart';
 import '../repository/feeds_repository.dart';
-import 'event/member_list_event_handler.dart';
+import 'event/handler/member_list_event_handler.dart';
 import 'member_list_state.dart';
 import 'query/members_query.dart';
 import 'state_notifier_extentions.dart';
diff --git a/packages/stream_feeds/lib/src/state/poll_list.dart b/packages/stream_feeds/lib/src/state/poll_list.dart
index 6616ef8b..e2b5c6c2 100644
--- a/packages/stream_feeds/lib/src/state/poll_list.dart
+++ b/packages/stream_feeds/lib/src/state/poll_list.dart
@@ -7,7 +7,7 @@ import 'package:stream_core/stream_core.dart';
 import '../models/poll_data.dart';
 import '../models/query_configuration.dart';
 import '../repository/polls_repository.dart';
-import 'event/poll_list_event_handler.dart';
+import 'event/handler/poll_list_event_handler.dart';
 import 'poll_list_state.dart';
 import 'query/polls_query.dart';
 import 'state_notifier_extentions.dart';
diff --git a/packages/stream_feeds/lib/src/state/poll_vote_list.dart b/packages/stream_feeds/lib/src/state/poll_vote_list.dart
index b207f3d6..9edbdf4b 100644
--- a/packages/stream_feeds/lib/src/state/poll_vote_list.dart
+++ b/packages/stream_feeds/lib/src/state/poll_vote_list.dart
@@ -7,7 +7,7 @@ import 'package:stream_core/stream_core.dart';
 import '../models/poll_vote_data.dart';
 import '../models/query_configuration.dart';
 import '../repository/polls_repository.dart';
-import 'event/poll_vote_list_event_handler.dart';
+import 'event/handler/poll_vote_list_event_handler.dart';
 import 'poll_vote_list_state.dart';
 import 'query/poll_votes_query.dart';
 import 'state_notifier_extentions.dart';
diff --git a/packages/stream_feeds/lib/src/utils/filter.dart b/packages/stream_feeds/lib/src/utils/filter.dart
index b534c54e..0f792708 100644
--- a/packages/stream_feeds/lib/src/utils/filter.dart
+++ b/packages/stream_feeds/lib/src/utils/filter.dart
@@ -5,3 +5,11 @@ extension FilterRequestExtension on Filter {
   /// Converts this [Filter] instance to a request format suitable for API calls.
   Map<String, Object?> toRequest() => toJson();
 }
+
+/// Extension to check if an object [T] matches a given filter.
+extension MatchesExtensions<T extends Object> on T {
+  /// Null filter means "no filter", so everything matches.
+  bool matches(Filter<T>? filter) {
+    return filter == null || filter.matches(this);
+  }
+}
diff --git a/packages/stream_feeds/test/state/feed_test.dart b/packages/stream_feeds/test/state/feed_test.dart
index 37c285da..7bd2eb3e 100644
--- a/packages/stream_feeds/test/state/feed_test.dart
+++ b/packages/stream_feeds/test/state/feed_test.dart
@@ -1,6 +1,7 @@
 // ignore_for_file: avoid_redundant_argument_values
 
 import 'package:mocktail/mocktail.dart';
+import 'package:stream_feeds/src/utils/filter.dart';
 import 'package:stream_feeds/stream_feeds.dart';
 import 'package:test/test.dart';
 
@@ -751,6 +752,7 @@ void main() {
             fid: feedId.rawValue,
             activity: createDefaultActivityResponse(
               id: 'activity-4',
+              userId: 'luke_skywalker',
             ).copyWith(
               type: 'post', // Matches first condition
               filterTags: ['general'], // Doesn't match second condition
@@ -790,6 +792,7 @@ void main() {
             fid: feedId.rawValue,
             activity: createDefaultActivityResponse(
               id: 'activity-4',
+              userId: 'luke_skywalker',
               // Doesn't match 'post' activity type
             ).copyWith(type: 'post'),
           ),
@@ -1805,4 +1808,293 @@ void main() {
       },
     );
   });
+
+  // ============================================================
+  // FEATURE: OnNewActivity
+  // ============================================================
+
+  group('OnNewActivity', () {
+    const feedId = FeedId(group: 'user', id: 'john');
+    const currentUserId = 'luke_skywalker';
+    const otherUserId = 'other_user';
+
+    final initialActivities = [
+      createDefaultActivityResponse(id: 'activity-1', userId: currentUserId),
+      createDefaultActivityResponse(id: 'activity-2', userId: currentUserId),
+      createDefaultActivityResponse(id: 'activity-3', userId: otherUserId),
+    ];
+
+    feedTest(
+      'defaultOnNewActivity - should add current user activity to start when matching filter',
+      build: (client) => client.feedFromQuery(
+        FeedQuery(
+          fid: feedId,
+          activityFilter: Filter.equal(
+            ActivitiesFilterField.activityType,
+            'post',
+          ),
+        ),
+      ),
+      setUp: (tester) => tester.getOrCreate(
+        modifyResponse: (it) => it.copyWith(activities: initialActivities),
+      ),
+      body: (tester) async {
+        expect(tester.feedState.activities, hasLength(3));
+
+        // Send ActivityAddedEvent from current user matching filter
+        await tester.emitEvent(
+          ActivityAddedEvent(
+            type: EventTypes.activityAdded,
+            createdAt: DateTime.timestamp(),
+            custom: const {},
+            fid: feedId.rawValue,
+            activity: createDefaultActivityResponse(
+              id: 'activity-4',
+              userId: currentUserId,
+              type: 'post',
+            ),
+          ),
+        );
+
+        expect(tester.feedState.activities, hasLength(4));
+        expect(tester.feedState.activities.first.id, 'activity-4');
+      },
+    );
+
+    feedTest(
+      'defaultOnNewActivity - should ignore activity from other user',
+      build: (client) => client.feedFromQuery(
+        FeedQuery(
+          fid: feedId,
+          activityFilter: Filter.equal(
+            ActivitiesFilterField.activityType,
+            'post',
+          ),
+        ),
+      ),
+      setUp: (tester) => tester.getOrCreate(
+        modifyResponse: (it) => it.copyWith(activities: initialActivities),
+      ),
+      body: (tester) async {
+        expect(tester.feedState.activities, hasLength(3));
+
+        // Send ActivityAddedEvent from other user
+        await tester.emitEvent(
+          ActivityAddedEvent(
+            type: EventTypes.activityAdded,
+            createdAt: DateTime.timestamp(),
+            custom: const {},
+            fid: feedId.rawValue,
+            activity: createDefaultActivityResponse(
+              id: 'activity-4',
+              userId: otherUserId,
+              type: 'post',
+            ),
+          ),
+        );
+
+        expect(tester.feedState.activities, hasLength(3));
+      },
+    );
+
+    feedTest(
+      'defaultOnNewActivity - should ignore current user activity that does not match filter',
+      build: (client) => client.feedFromQuery(
+        FeedQuery(
+          fid: feedId,
+          activityFilter: Filter.equal(
+            ActivitiesFilterField.activityType,
+            'post',
+          ),
+        ),
+      ),
+      setUp: (tester) => tester.getOrCreate(
+        modifyResponse: (it) => it.copyWith(activities: initialActivities),
+      ),
+      body: (tester) async {
+        expect(tester.feedState.activities, hasLength(3));
+
+        // Send ActivityAddedEvent from current user but doesn't match filter
+        await tester.emitEvent(
+          ActivityAddedEvent(
+            type: EventTypes.activityAdded,
+            createdAt: DateTime.timestamp(),
+            custom: const {},
+            fid: feedId.rawValue,
+            activity: createDefaultActivityResponse(
+              id: 'activity-4',
+              userId: currentUserId,
+              type: 'comment', // Doesn't match 'post' filter
+            ),
+          ),
+        );
+
+        expect(tester.feedState.activities, hasLength(3));
+      },
+    );
+
+    feedTest(
+      'custom onNewActivity - should add to start',
+      build: (client) => client.feedFromQuery(
+        const FeedQuery(fid: feedId),
+        onNewActivity: (query, activity, currentUserId) {
+          // Always add to start
+          return InsertionAction.addToStart;
+        },
+      ),
+      setUp: (tester) => tester.getOrCreate(
+        modifyResponse: (it) => it.copyWith(activities: initialActivities),
+      ),
+      body: (tester) async {
+        expect(tester.feedState.activities, hasLength(3));
+
+        // Send ActivityAddedEvent from other user
+        await tester.emitEvent(
+          ActivityAddedEvent(
+            type: EventTypes.activityAdded,
+            createdAt: DateTime.timestamp(),
+            custom: const {},
+            fid: feedId.rawValue,
+            activity: createDefaultActivityResponse(
+              id: 'activity-4',
+              userId: otherUserId,
+            ),
+          ),
+        );
+
+        expect(tester.feedState.activities, hasLength(4));
+        expect(tester.feedState.activities.first.id, 'activity-4');
+      },
+    );
+
+    feedTest(
+      'custom onNewActivity - should add to end',
+      build: (client) => client.feedFromQuery(
+        const FeedQuery(fid: feedId),
+        onNewActivity: (query, activity, currentUserId) {
+          // Always add to end
+          return InsertionAction.addToEnd;
+        },
+      ),
+      setUp: (tester) => tester.getOrCreate(
+        modifyResponse: (it) => it.copyWith(activities: initialActivities),
+      ),
+      body: (tester) async {
+        expect(tester.feedState.activities, hasLength(3));
+
+        // Send ActivityAddedEvent from other user
+        await tester.emitEvent(
+          ActivityAddedEvent(
+            type: EventTypes.activityAdded,
+            createdAt: DateTime.timestamp(),
+            custom: const {},
+            fid: feedId.rawValue,
+            activity: createDefaultActivityResponse(
+              id: 'activity-4',
+              userId: otherUserId,
+            ),
+          ),
+        );
+
+        expect(tester.feedState.activities, hasLength(4));
+        expect(tester.feedState.activities.last.id, 'activity-4');
+      },
+    );
+
+    feedTest(
+      'custom onNewActivity - should ignore',
+      build: (client) => client.feedFromQuery(
+        const FeedQuery(fid: feedId),
+        onNewActivity: (query, activity, currentUserId) {
+          // Always ignore
+          return InsertionAction.ignore;
+        },
+      ),
+      setUp: (tester) => tester.getOrCreate(
+        modifyResponse: (it) => it.copyWith(activities: initialActivities),
+      ),
+      body: (tester) async {
+        expect(tester.feedState.activities, hasLength(3));
+
+        // Send ActivityAddedEvent from current user
+        await tester.emitEvent(
+          ActivityAddedEvent(
+            type: EventTypes.activityAdded,
+            createdAt: DateTime.timestamp(),
+            custom: const {},
+            fid: feedId.rawValue,
+            activity: createDefaultActivityResponse(
+              id: 'activity-4',
+              userId: currentUserId,
+            ),
+          ),
+        );
+
+        expect(tester.feedState.activities, hasLength(3));
+      },
+    );
+
+    feedTest(
+      'custom onNewActivity - should use query and activity context',
+      build: (client) => client.feedFromQuery(
+        FeedQuery(
+          fid: feedId,
+          activityFilter: Filter.equal(
+            ActivitiesFilterField.activityType,
+            'post',
+          ),
+        ),
+        onNewActivity: (query, activity, currentUserId) {
+          // Add activities from other users that match the filter to the end
+          if (activity.user.id != currentUserId) {
+            if (activity.matches(query.activityFilter)) {
+              return InsertionAction.addToEnd;
+            }
+          }
+          return InsertionAction.ignore;
+        },
+      ),
+      setUp: (tester) => tester.getOrCreate(
+        modifyResponse: (it) => it.copyWith(activities: initialActivities),
+      ),
+      body: (tester) async {
+        expect(tester.feedState.activities, hasLength(3));
+
+        // Send ActivityAddedEvent from other user matching filter
+        await tester.emitEvent(
+          ActivityAddedEvent(
+            type: EventTypes.activityAdded,
+            createdAt: DateTime.timestamp(),
+            custom: const {},
+            fid: feedId.rawValue,
+            activity: createDefaultActivityResponse(
+              id: 'activity-4',
+              userId: otherUserId,
+              type: 'post',
+            ),
+          ),
+        );
+
+        expect(tester.feedState.activities, hasLength(4));
+        expect(tester.feedState.activities.last.id, 'activity-4');
+
+        // Send ActivityAddedEvent from other user not matching filter
+        await tester.emitEvent(
+          ActivityAddedEvent(
+            type: EventTypes.activityAdded,
+            createdAt: DateTime.timestamp(),
+            custom: const {},
+            fid: feedId.rawValue,
+            activity: createDefaultActivityResponse(
+              id: 'activity-5',
+              userId: otherUserId,
+              type: 'comment', // Doesn't match 'post' filter
+            ),
+          ),
+        );
+
+        expect(tester.feedState.activities, hasLength(4));
+      },
+    );
+  });
 }
diff --git a/packages/stream_feeds/test/test_utils/fakes.dart b/packages/stream_feeds/test/test_utils/fakes.dart
index 286bebdd..85401b86 100644
--- a/packages/stream_feeds/test/test_utils/fakes.dart
+++ b/packages/stream_feeds/test/test_utils/fakes.dart
@@ -83,6 +83,7 @@ GetActivityResponse createDefaultGetActivityResponse({
 ActivityResponse createDefaultActivityResponse({
   String id = 'id',
   String type = 'post',
+  String userId = 'user-1',
   List<String> feeds = const [],
   PollResponseData? poll,
   bool hidden = false,
@@ -125,7 +126,7 @@ ActivityResponse createDefaultActivityResponse({
     type: type,
     isWatched: isWatched,
     updatedAt: DateTime(2021, 2, 1),
-    user: createDefaultUserResponse(),
+    user: createDefaultUserResponse(id: userId),
     visibility: ActivityResponseVisibility.public,
     visibilityTag: null,
   );
diff --git a/sample_app/lib/screens/user_feed/user_feed_screen.dart b/sample_app/lib/screens/user_feed/user_feed_screen.dart
index 48c48703..47c22cb8 100644
--- a/sample_app/lib/screens/user_feed/user_feed_screen.dart
+++ b/sample_app/lib/screens/user_feed/user_feed_screen.dart
@@ -30,6 +30,11 @@ class _UserFeedScreenState extends State<UserFeedScreen> {
 
   late final storiesFeed = client.feedFromId(
     FeedId.stories(client.user.id),
+    onNewActivity: (query, activity, currentUserId) {
+      // By default new activities are added to the start of the list,
+      // but this is not what we want for stories
+      return InsertionAction.addToEnd;
+    },
   );
 
   late final userFeed = client.feedFromQuery(