diff --git a/packages/genui/lib/genui.dart b/packages/genui/lib/genui.dart
index 525d64ba4..290601909 100644
--- a/packages/genui/lib/genui.dart
+++ b/packages/genui/lib/genui.dart
@@ -29,6 +29,7 @@ export 'src/model/chat_message.dart';
 export 'src/model/data_model.dart';
 export 'src/model/generation_events.dart';
 export 'src/model/ui_models.dart';
+export 'src/model/validation_helper.dart';
 export 'src/primitives/cancellation.dart';
 export 'src/primitives/constants.dart';
 export 'src/primitives/logging.dart';
diff --git a/packages/genui/lib/src/catalog/basic_catalog_widgets/button.dart b/packages/genui/lib/src/catalog/basic_catalog_widgets/button.dart
index b1d719498..9c50c80b2 100644
--- a/packages/genui/lib/src/catalog/basic_catalog_widgets/button.dart
+++ b/packages/genui/lib/src/catalog/basic_catalog_widgets/button.dart
@@ -7,11 +7,11 @@ import 'package:json_schema_builder/json_schema_builder.dart';
 
 import '../../model/a2ui_schemas.dart';
 import '../../model/catalog_item.dart';
+import '../../model/data_model.dart';
 import '../../model/ui_models.dart';
+import '../../model/validation_helper.dart';
 import '../../primitives/logging.dart';
 import '../../primitives/simple_items.dart';
-import '../../utils/validation_helper.dart';
-import '../../widgets/widget_utilities.dart';
 
 final _schema = S.object(
   description: 'An interactive button that triggers an action when pressed.',
diff --git a/packages/genui/lib/src/catalog/basic_catalog_widgets/date_time_input.dart b/packages/genui/lib/src/catalog/basic_catalog_widgets/date_time_input.dart
index c2401d6c4..be314b50d 100644
--- a/packages/genui/lib/src/catalog/basic_catalog_widgets/date_time_input.dart
+++ b/packages/genui/lib/src/catalog/basic_catalog_widgets/date_time_input.dart
@@ -10,8 +10,8 @@ import 'package:json_schema_builder/json_schema_builder.dart';
 import '../../model/a2ui_schemas.dart';
 import '../../model/catalog_item.dart';
 import '../../model/data_model.dart';
+import '../../model/validation_helper.dart';
 import '../../primitives/simple_items.dart';
-import '../../utils/validation_helper.dart';
 import '../../widgets/widget_utilities.dart';
 
 final _schema = S.object(
diff --git a/packages/genui/lib/src/catalog/basic_catalog_widgets/text_field.dart b/packages/genui/lib/src/catalog/basic_catalog_widgets/text_field.dart
index 577ecb9ce..cad6e5c0c 100644
--- a/packages/genui/lib/src/catalog/basic_catalog_widgets/text_field.dart
+++ b/packages/genui/lib/src/catalog/basic_catalog_widgets/text_field.dart
@@ -11,8 +11,8 @@ import '../../model/a2ui_schemas.dart';
 import '../../model/catalog_item.dart';
 import '../../model/data_model.dart';
 import '../../model/ui_models.dart';
+import '../../model/validation_helper.dart';
 import '../../primitives/simple_items.dart';
-import '../../utils/validation_helper.dart';
 import '../../widgets/widget_utilities.dart';
 
 final _schema = S.object(
diff --git a/packages/genui/lib/src/functions/format_string.dart b/packages/genui/lib/src/functions/format_string.dart
index 51e44edc0..c1aaa9a00 100644
--- a/packages/genui/lib/src/functions/format_string.dart
+++ b/packages/genui/lib/src/functions/format_string.dart
@@ -4,12 +4,13 @@
 
 import 'package:json_schema_builder/json_schema_builder.dart';
 import 'package:meta/meta.dart';
-import 'package:rxdart/rxdart.dart';
+import 'package:stream_transform/stream_transform.dart';
 
 import '../model/client_function.dart' as cf;
 import '../model/data_model.dart';
 import '../primitives/logging.dart';
 import '../primitives/simple_items.dart';
+import '../utils/stream_extensions.dart';
 
 /// Formats a value as a string.
 class FormatStringFunction implements cf.ClientFunction {
@@ -173,7 +174,7 @@ class ExpressionParser {
       return Stream<Object?>.value(val);
     }).toList();
 
-    return CombineLatestStream.list(streams).switchMap((List<Object?> values) {
+    return streams.combineLatestAll().switchMap((List<Object?> values) {
       final Map<String, Object?> combinedArgs = {};
       for (var i = 0; i < keys.length; i++) {
         combinedArgs[keys[i]] = values[i];
@@ -249,7 +250,7 @@ class ExpressionParser {
       return Stream<Object?>.value(part);
     }).toList();
 
-    return CombineLatestStream.list(streams).map((List<Object?> values) {
+    return streams.combineLatestAll().map((List<Object?> values) {
       return values.map((e) => e?.toString() ?? '').join('');
     });
   }
diff --git a/packages/genui/lib/src/model/data_model.dart b/packages/genui/lib/src/model/data_model.dart
index 2aba001ab..cdd031110 100644
--- a/packages/genui/lib/src/model/data_model.dart
+++ b/packages/genui/lib/src/model/data_model.dart
@@ -6,10 +6,11 @@ import 'dart:async';
 import 'dart:convert';
 
 import 'package:flutter/foundation.dart';
-import 'package:rxdart/rxdart.dart';
+import 'package:stream_transform/stream_transform.dart';
 
 import '../primitives/logging.dart';
 import '../primitives/simple_items.dart';
+import '../utils/stream_extensions.dart';
 import 'client_function.dart' as cf;
 
 import 'data_path.dart';
@@ -155,7 +156,7 @@ class DataContext implements cf.ExecutionContext {
 
     final Stream<List<Object?>> combinedStream = streams.isEmpty
         ? Stream.value([])
-        : CombineLatestStream.list(streams);
+        : streams.combineLatestAll();
 
     return combinedStream.switchMap((List<Object?> values) {
       final Map<String, Object?> combinedArgs = {};
@@ -180,6 +181,23 @@ class DataContext implements cf.ExecutionContext {
   }
 }
 
+/// Resolves a context map definition against a [DataContext].
+///
+Future<JsonMap> resolveContext(
+  DataContext dataContext,
+  JsonMap? contextDefinition,
+) async {
+  final resolved = <String, Object?>{};
+  if (contextDefinition == null) return resolved;
+
+  for (final MapEntry<String, Object?> entry in contextDefinition.entries) {
+    final String key = entry.key;
+    final Object? value = entry.value;
+    resolved[key] = await dataContext.resolve(value).first;
+  }
+  return resolved;
+}
+
 /// Exception thrown when a value in the [DataModel] is not of the expected
 /// type.
 class DataModelTypeException implements Exception {
diff --git a/packages/genui/lib/src/utils/validation_helper.dart b/packages/genui/lib/src/model/validation_helper.dart
similarity index 94%
rename from packages/genui/lib/src/utils/validation_helper.dart
rename to packages/genui/lib/src/model/validation_helper.dart
index eaf6262b7..731ce2e59 100644
--- a/packages/genui/lib/src/utils/validation_helper.dart
+++ b/packages/genui/lib/src/model/validation_helper.dart
@@ -2,11 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:rxdart/rxdart.dart';
-
-import '../model/data_model.dart';
 import '../primitives/simple_items.dart';
-import '../widgets/widget_utilities.dart';
+import '../utils/stream_extensions.dart';
+import 'data_model.dart';
 
 /// A validation error with a message.
 class ValidationError {
@@ -47,7 +45,7 @@ class ValidationHelper {
       );
     }
 
-    return CombineLatestStream.list(streams).map((results) {
+    return streams.combineLatestAll().map((results) {
       for (final (isValid, msg) in results) {
         if (!isValid) return msg;
       }
diff --git a/packages/genui/lib/src/utils/stream_extensions.dart b/packages/genui/lib/src/utils/stream_extensions.dart
new file mode 100644
index 000000000..87e85d8e8
--- /dev/null
+++ b/packages/genui/lib/src/utils/stream_extensions.dart
@@ -0,0 +1,19 @@
+// Copyright 2025 The Flutter Authors.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:stream_transform/stream_transform.dart';
+
+/// Extensions for [Iterable] of [Stream]s.
+extension CombineLatestAll<T> on Iterable<Stream<T>> {
+  /// Combines all streams in this iterable into a single stream that emits a
+  /// list of the latest values from each stream.
+  ///
+  /// The resulting stream will not emit until every stream in the iterable has
+  /// emitted at least one value.
+  Stream<List<T>> combineLatestAll() {
+    if (isEmpty) return Stream.value([]);
+
+    return first.combineLatestAll(skip(1));
+  }
+}
diff --git a/packages/genui/lib/src/widgets/widget_utilities.dart b/packages/genui/lib/src/widgets/widget_utilities.dart
index b7ef26584..e356a785c 100644
--- a/packages/genui/lib/src/widgets/widget_utilities.dart
+++ b/packages/genui/lib/src/widgets/widget_utilities.dart
@@ -9,7 +9,8 @@ import 'package:flutter/material.dart';
 
 import '../model/data_model.dart';
 import '../primitives/logging.dart';
-import '../primitives/simple_items.dart';
+
+export '../model/data_model.dart' show resolveContext;
 
 /// A builder widget that simplifies handling of nullable `ValueListenable`s.
 ///
@@ -376,20 +377,3 @@ class _ToNumberNotifier extends ValueNotifier<num?> {
     super.dispose();
   }
 }
-
-/// Resolves a context map definition against a [DataContext].
-///
-Future<JsonMap> resolveContext(
-  DataContext dataContext,
-  JsonMap? contextDefinition,
-) async {
-  final resolved = <String, Object?>{};
-  if (contextDefinition == null) return resolved;
-
-  for (final MapEntry<String, Object?> entry in contextDefinition.entries) {
-    final String key = entry.key;
-    final Object? value = entry.value;
-    resolved[key] = await dataContext.resolve(value).first;
-  }
-  return resolved;
-}
diff --git a/packages/genui/pubspec.yaml b/packages/genui/pubspec.yaml
index 17141b3ea..79d7769fe 100644
--- a/packages/genui/pubspec.yaml
+++ b/packages/genui/pubspec.yaml
@@ -25,7 +25,7 @@ dependencies:
   json_schema_builder: ^0.1.3
   logging: ^1.3.0
   meta: ^1.17.0
-  rxdart: ^0.28.0
+  stream_transform: ^2.1.1
   url_launcher: ^6.3.2
   uuid: ^4.4.0