Prefix json_annotation helpers when imported with a prefix

json_serializable/lib/src/decode_helper.dart

@@ -90,9 +90,10 @@ mixin DecodeHelper implements HelperCore {
     if (config.checked) {
       final classLiteral = escapeDartString(element.name!);
 
+      final helperPrefix = jsonAnnotationHelperPrefix(element.library);
       final sectionBuffer = StringBuffer()
         ..write('''
-  \$checkedCreate(
+  ${helperPrefix}\$checkedCreate(
     $classLiteral,
     json,
     (\$checkedConvert) {\n''')
@@ -202,7 +203,8 @@ mixin DecodeHelper implements HelperCore {
     }
 
     if (args.isNotEmpty) {
-      yield '\$checkKeys(json, ${args.map((e) => '$e, ').join()});\n';
+      final helperPrefix = jsonAnnotationHelperPrefix(element.library);
+      yield '${helperPrefix}\$checkKeys(json, ${args.map((e) => '$e, ').join()});\n';
     }
   }
 

json_serializable/lib/src/type_helpers/enum_helper.dart

@@ -9,6 +9,7 @@ import 'package:source_helper/source_helper.dart';
 import '../enum_utils.dart';
 import '../json_key_utils.dart';
 import '../type_helper.dart';
+import '../utils.dart';
 
 final simpleExpression = RegExp('^[a-zA-Z_]+\$');
 
@@ -62,11 +63,14 @@ class EnumHelper extends TypeHelper<TypeHelperContextWithConfig> {
       );
     }
 
-    String functionName;
+    final helperPrefix = jsonAnnotationHelperPrefix(
+      context.classElement.library,
+    );
+    final String functionName;
     if (targetType.isNullableType || defaultProvided) {
-      functionName = r'$enumDecodeNullable';
+      functionName = '${helperPrefix}\$enumDecodeNullable';
     } else {
-      functionName = r'$enumDecode';
+      functionName = '${helperPrefix}\$enumDecode';
     }
 
     context.addMember(memberContent);

json_serializable/lib/src/utils.dart

@@ -304,3 +304,26 @@ extension ExecutableElementExtension on ExecutableElement {
 const jsonSerializableChecker = TypeChecker.fromUrl(
   'package:json_annotation/src/json_serializable.dart#JsonSerializable',
 );
+
+/// Returns the import prefix used for `package:json_annotation`, including a
+/// trailing `.`, or an empty string when the import is unprefixed.
+///
+/// Generated references to helpers like `$checkedCreate` and `$enumDecode` must
+/// use this prefix so they resolve when the annotation library is imported with
+/// a prefix.
+String jsonAnnotationHelperPrefix(LibraryElement library) {
+  for (final fragment in library.fragments) {
+    for (final import in fragment.libraryImports) {
+      final uri = import.importedLibrary?.uri;
+      if (uri == null ||
+          uri.scheme != 'package' ||
+          uri.pathSegments.isEmpty ||
+          uri.pathSegments.first != 'json_annotation') {
+        continue;
+      }
+      final prefix = import.prefix?.name;
+      return prefix == null ? '' : '$prefix.';
+    }
+  }
+  return '';
+}

json_serializable/test/integration/integration_test.dart

@@ -9,6 +9,7 @@ import '../test_utils.dart';
 import 'converter_examples.dart';
 import 'create_per_field_to_json_example.dart';
 import 'field_map_example.dart';
+import 'json_annotation_prefix_example.dart';
 import 'json_enum_example.dart';
 import 'json_keys_example.dart' as js_keys;
 import 'json_test_common.dart' show Category, Platform, StatusCode;
@@ -492,4 +493,15 @@ void main() {
     )..remove(r'$schema');
     expect(nestedSchemaFromExample, standaloneSchema);
   });
+
+  test('json_annotation import prefix helpers', () {
+    final checked = CheckedPrefixModel.fromJson({'field1': 'a', 'field2': 'b'});
+    expect(checked.field1, 'a');
+    expect(checked.field2, 'b');
+    expect(checked.toJson(), {'field1': 'a', 'field2': 'b'});
+
+    final enumModel = EnumPrefixModel.fromJson({'gender': 'female'});
+    expect(enumModel.gender, PrefixModelGender.female);
+    expect(enumModel.toJson(), {'gender': 'female'});
+  });
 }

json_serializable/test/integration/json_annotation_prefix_example.dart

@@ -0,0 +1,31 @@
+import 'package:json_annotation/json_annotation.dart' as ja;
+
+part 'json_annotation_prefix_example.g.dart';
+
+@ja.JsonSerializable(checked: true)
+class CheckedPrefixModel {
+  final String field1;
+  final String field2;
+
+  CheckedPrefixModel({required this.field1, required this.field2});
+
+  factory CheckedPrefixModel.fromJson(Map<String, dynamic> json) =>
+      _$CheckedPrefixModelFromJson(json);
+
+  Map<String, dynamic> toJson() => _$CheckedPrefixModelToJson(this);
+}
+
+@ja.JsonSerializable()
+class EnumPrefixModel {
+  @ja.JsonKey(required: true, disallowNullValue: true)
+  final PrefixModelGender gender;
+
+  EnumPrefixModel({required this.gender});
+
+  factory EnumPrefixModel.fromJson(Map<String, dynamic> json) =>
+      _$EnumPrefixModelFromJson(json);
+
+  Map<String, dynamic> toJson() => _$EnumPrefixModelToJson(this);
+}
+
+enum PrefixModelGender { male, female, other }

json_serializable/test/json_serializable_test.dart

@@ -50,6 +50,18 @@ Future<void> main() async {
       'UnsupportedClass',
     },
   );
+
+  final jsonAnnotationPrefixTestReader =
+      await initializeLibraryReaderForDirectory(
+        p.join('test', 'src'),
+        '_json_annotation_prefix_test_input.dart',
+      );
+
+  testAnnotatedElements(
+    jsonAnnotationPrefixTestReader,
+    JsonSerializableGenerator(),
+    expectedAnnotatedTests: {'CheckedWithPrefix', 'EnumWithPrefix'},
+  );
 }
 
 const _expectedAnnotatedTests = {

json_serializable/test/src/_json_annotation_prefix_test_input.dart

@@ -0,0 +1,52 @@
+// Copyright (c) 2026, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// @dart=3.8
+
+import 'package:json_annotation/json_annotation.dart' as ja;
+import 'package:source_gen_test/annotations.dart';
+
+@ShouldGenerate(r'''
+CheckedWithPrefix _$CheckedWithPrefixFromJson(Map<String, dynamic> json) =>
+    ja.$checkedCreate('CheckedWithPrefix', json, ($checkedConvert) {
+      final val = CheckedWithPrefix(
+        $checkedConvert('field1', (v) => v as String),
+        $checkedConvert('field2', (v) => v as String),
+      );
+      return val;
+    });
+''')
+@ja.JsonSerializable(checked: true, createToJson: false)
+class CheckedWithPrefix {
+  final String field1;
+  final String field2;
+
+  CheckedWithPrefix(this.field1, this.field2);
+}
+
+@ShouldGenerate(r'''
+EnumWithPrefix _$EnumWithPrefixFromJson(Map<String, dynamic> json) {
+  ja.$checkKeys(
+    json,
+    requiredKeys: const ['gender'],
+    disallowNullValues: const ['gender'],
+  );
+  return EnumWithPrefix(ja.$enumDecode(_$PrefixGenderEnumMap, json['gender']));
+}
+
+const _$PrefixGenderEnumMap = {
+  PrefixGender.male: 'male',
+  PrefixGender.female: 'female',
+  PrefixGender.other: 'other',
+};
+''')
+@ja.JsonSerializable(createToJson: false)
+class EnumWithPrefix {
+  @ja.JsonKey(required: true, disallowNullValue: true)
+  final PrefixGender gender;
+
+  EnumWithPrefix(this.gender);
+}
+
+enum PrefixGender { male, female, other }