diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4917265a24..bbcd28ab28 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,7 +14,7 @@
 - remove the `package:args` dependency #94
 - move the `package:pedantic` to dev depencies #94
 - Added GH Action Changelog verifier #95
-- Added GH Action (CI) for Dart
+- Added GH Action (CI) for Dart #97
 - new Dart code file structure #96 
 - Base the sdk name on the platform (`sentry.dart` for io & flutter, `sentry.dart.browser` in a browser context) #103 
 - Single changelog and readme for both packages #105
@@ -22,10 +22,11 @@
 - expect a sdkName based on the test platform #105
 - Added Scope and Breadcrumb ring buffer #109
 - Added Hub to SDK #113
-- Ref: Hub passes the Scope to SentryClient
+- Ref: Hub passes the Scope to SentryClient #114
 - Feature: sentry options #116
-- Ref: SentryId generates UUID
-- Ref: Event now is SentryEvent and added GPU
+- Ref: SentryId generates UUID #119
+- Ref: Event now is SentryEvent and added GPU #121
+- Feat: before breadcrumb and scope ref. #122
 
 # `package:sentry` changelog
 
diff --git a/dart/lib/src/scope.dart b/dart/lib/src/scope.dart
index 11c2530795..4927fcaa5b 100644
--- a/dart/lib/src/scope.dart
+++ b/dart/lib/src/scope.dart
@@ -6,32 +6,14 @@ import 'sentry_options.dart';
 /// Scope data to be sent with the event
 class Scope {
   /// How important this event is.
-  SentryLevel _level;
-
-  SentryLevel get level => _level;
-
-  set level(SentryLevel level) {
-    _level = level;
-  }
+  SentryLevel level;
 
   /// The name of the transaction which generated this event,
   /// for example, the route name: `"/users/<username>/"`.
-  String _transaction;
-
-  String get transaction => _transaction;
-
-  set transaction(String transaction) {
-    _transaction = transaction;
-  }
+  String transaction;
 
   /// Information about the current user.
-  User _user;
-
-  User get user => _user;
-
-  set user(User user) {
-    _user = user;
-  }
+  User user;
 
   /// Used to deduplicate events by grouping ones with the same fingerprint
   /// together.
@@ -71,14 +53,20 @@ class Scope {
 
   Map<String, dynamic> get extra => Map.unmodifiable(_extra);
 
-  // TODO: EventProcessors, Contexts, BeforeBreadcrumbCallback, Breadcrumb Hint, clone
+  // TODO: Contexts
+
+  /// Scope's event processor list
+  final List<EventProcessor> _eventProcessors = [];
+
+  List<EventProcessor> get eventProcessors =>
+      List.unmodifiable(_eventProcessors);
 
   final SentryOptions _options;
 
   Scope(this._options) : assert(_options != null, 'SentryOptions is required');
 
   /// Adds a breadcrumb to the breadcrumbs queue
-  void addBreadcrumb(Breadcrumb breadcrumb) {
+  void addBreadcrumb(Breadcrumb breadcrumb, {dynamic hint}) {
     assert(breadcrumb != null, "Breadcrumb can't be null");
 
     // bail out if maxBreadcrumbs is zero
@@ -86,6 +74,17 @@ class Scope {
       return;
     }
 
+    // run before breadcrumb callback if set
+    if (_options.beforeBreadcrumbCallback != null) {
+      breadcrumb = _options.beforeBreadcrumbCallback(breadcrumb, hint);
+
+      if (breadcrumb == null) {
+        _options.logger(
+            SentryLevel.info, 'Breadcrumb was dropped by beforeBreadcrumb');
+        return;
+      }
+    }
+
     // remove first item if list if full
     if (_breadcrumbs.length >= _options.maxBreadcrumbs &&
         _breadcrumbs.isNotEmpty) {
@@ -100,15 +99,23 @@ class Scope {
     _breadcrumbs.clear();
   }
 
+  /// Adds an event processor
+  void addEventProcessor(EventProcessor eventProcessor) {
+    assert(eventProcessor != null, "EventProcessor can't be null");
+
+    _eventProcessors.add(eventProcessor);
+  }
+
   /// Resets the Scope to its default state
   void clear() {
     clearBreadcrumbs();
-    _level = null;
-    _transaction = null;
-    _user = null;
+    level = null;
+    transaction = null;
+    user = null;
     _fingerprint = null;
     _tags.clear();
     _extra.clear();
+    _eventProcessors.clear();
   }
 
   /// Sets a tag to the Scope
@@ -135,6 +142,7 @@ class Scope {
   /// Removes an extra from the Scope
   void removeExtra(String key) => _extra.remove(key);
 
+  /// Clones the current Scope
   Scope clone() {
     final clone = Scope(_options)
       ..user = user
@@ -153,6 +161,10 @@ class Scope {
       clone.addBreadcrumb(breadcrumb);
     }
 
+    for (final eventProcessor in _eventProcessors) {
+      clone.addEventProcessor(eventProcessor);
+    }
+
     return clone;
   }
 }
diff --git a/dart/test/scope_test.dart b/dart/test/scope_test.dart
index d7fcea8edf..f539930405 100644
--- a/dart/test/scope_test.dart
+++ b/dart/test/scope_test.dart
@@ -48,6 +48,25 @@ void main() {
     expect(sut.breadcrumbs.last, breadcrumb);
   });
 
+  test('Executes and drops $Breadcrumb', () {
+    final sut = fixture.getSut(
+      beforeBreadcrumbCallback: fixture.beforeBreadcrumbCallback,
+    );
+
+    final breadcrumb = Breadcrumb('test log', DateTime.utc(2019));
+    sut.addBreadcrumb(breadcrumb);
+
+    expect(sut.breadcrumbs.length, 0);
+  });
+
+  test('adds $EventProcessor', () {
+    final sut = fixture.getSut();
+
+    sut.addEventProcessor(fixture.processor);
+
+    expect(sut.eventProcessors.last, fixture.processor);
+  });
+
   test('respects max $Breadcrumb', () {
     final maxBreadcrumbs = 2;
     final sut = fixture.getSut(maxBreadcrumbs: maxBreadcrumbs);
@@ -149,6 +168,8 @@ void main() {
     sut.setTag('test', 'test');
     sut.setExtra('test', 'test');
 
+    sut.addEventProcessor(fixture.processor);
+
     sut.clear();
 
     expect(sut.breadcrumbs.length, 0);
@@ -164,6 +185,8 @@ void main() {
     expect(sut.tags.length, 0);
 
     expect(sut.extra.length, 0);
+
+    expect(sut.eventProcessors.length, 0);
   });
 
   test('clones', () {
@@ -175,13 +198,24 @@ void main() {
     expect(sut.tags, clone.tags);
     expect(sut.breadcrumbs, clone.breadcrumbs);
     expect(ListEquality().equals(sut.fingerprint, clone.fingerprint), true);
+    expect(ListEquality().equals(sut.eventProcessors, clone.eventProcessors),
+        true);
   });
 }
 
 class Fixture {
-  Scope getSut({int maxBreadcrumbs = 100}) {
+  Scope getSut({
+    int maxBreadcrumbs = 100,
+    BeforeBreadcrumbCallback beforeBreadcrumbCallback,
+  }) {
     final options = SentryOptions();
     options.maxBreadcrumbs = maxBreadcrumbs;
+    options.beforeBreadcrumbCallback = beforeBreadcrumbCallback;
     return Scope(options);
   }
+
+  SentryEvent processor(SentryEvent event, dynamic hint) => null;
+
+  Breadcrumb beforeBreadcrumbCallback(Breadcrumb breadcrumb, dynamic hint) =>
+      null;
 }