diff --git a/lib/model/Insight.dart b/lib/model/Insight.dart
index 113160bd35..9bef44e3c4 100644
--- a/lib/model/Insight.dart
+++ b/lib/model/Insight.dart
@@ -15,16 +15,27 @@ extension InsightAnnotationExtension on InsightAnnotation {
 }
 
 enum InsightType {
+  @JsonValue('ingredient_spellcheck')
   INGREDIENT_SPELLCHECK,
+  @JsonValue('packager_code')
   PACKAGER_CODE,
+  @JsonValue('label')
   LABEL,
+  @JsonValue('category')
   CATEGORY,
+  @JsonValue('product_weight')
   PRODUCT_WEIGHT,
+  @JsonValue('expiration_date')
   EXPIRATION_DATE,
+  @JsonValue('brand')
   BRAND,
+  @JsonValue('store')
   STORE,
+  @JsonValue('nutrient')
   NUTRIENT,
-  UNDEFINED
+  @JsonValue('undefined')
+  UNDEFINED,
+  UNKNOWN
 }
 
 extension InsightTypesExtension on InsightType? {
diff --git a/lib/model/RobotoffQuestion.dart b/lib/model/RobotoffQuestion.dart
index ff2e5ce81b..dad089a174 100644
--- a/lib/model/RobotoffQuestion.dart
+++ b/lib/model/RobotoffQuestion.dart
@@ -7,11 +7,7 @@ part 'RobotoffQuestion.g.dart';
 @JsonSerializable()
 class RobotoffQuestionResult extends JsonObject {
   final String? status;
-  @JsonKey(
-      name: 'questions',
-      includeIfNull: false,
-      fromJson: RobotoffQuestion.fromJson,
-      toJson: RobotoffQuestion.toJson)
+
   final List<RobotoffQuestion>? questions;
 
   const RobotoffQuestionResult({this.status, this.questions});
@@ -23,14 +19,15 @@ class RobotoffQuestionResult extends JsonObject {
   Map<String, dynamic> toJson() => _$RobotoffQuestionResultToJson(this);
 }
 
-class RobotoffQuestion {
+@JsonSerializable()
+class RobotoffQuestion extends JsonObject {
   final String? barcode;
   final String? type;
   final String? value;
   final String? question;
   @JsonKey(name: 'insight_id')
   final String? insightId;
-  @JsonKey(name: 'insight_type')
+  @JsonKey(name: 'insight_type', unknownEnumValue: InsightType.UNKNOWN)
   final InsightType? insightType;
   @JsonKey(name: 'source_image_url')
   final String? imageUrl;
@@ -44,44 +41,8 @@ class RobotoffQuestion {
       this.insightType,
       this.imageUrl});
 
-  static List<RobotoffQuestion> fromJson(List<dynamic> json) {
-    List<RobotoffQuestion> result = [];
-    for (Map<String, dynamic> jsonQuestion
-        in json as Iterable<Map<String, dynamic>>) {
-      InsightType insightType =
-          InsightTypesExtension.getType(jsonQuestion['insight_type']);
-
-      result.add(RobotoffQuestion(
-          barcode: jsonQuestion['barcode'],
-          type: jsonQuestion['type'],
-          value: jsonQuestion['value'],
-          question: jsonQuestion['question'],
-          insightId: jsonQuestion['insight_id'],
-          insightType: insightType,
-          imageUrl: jsonQuestion['source_image_url']));
-    }
-    return result;
-  }
-
-  static List<Map<String, dynamic>> toJson(List<RobotoffQuestion>? questions) {
-    if (questions == null) {
-      return [];
-    }
-    List<Map<String, dynamic>> result = [];
-
-    for (RobotoffQuestion question in questions) {
-      Map<String, String?> jsonQuestion = {};
-
-      jsonQuestion['barcode'] = question.barcode;
-      jsonQuestion['type'] = question.type;
-      jsonQuestion['value'] = question.value;
-      jsonQuestion['question'] = question.question;
-      jsonQuestion['insight_id'] = question.insightId;
-      jsonQuestion['insight_type'] = question.insightType.value;
-      jsonQuestion['insight_url'] = question.imageUrl;
+  factory RobotoffQuestion.fromJson(Map<String, dynamic> json) =>
+      _$RobotoffQuestionFromJson(json);
 
-      result.add(jsonQuestion);
-    }
-    return result;
-  }
+  Map<String, dynamic> toJson() => _$RobotoffQuestionToJson(this);
 }
diff --git a/lib/model/RobotoffQuestion.g.dart b/lib/model/RobotoffQuestion.g.dart
index 9c3d497ccc..8ae4ce5b08 100644
--- a/lib/model/RobotoffQuestion.g.dart
+++ b/lib/model/RobotoffQuestion.g.dart
@@ -10,21 +10,89 @@ RobotoffQuestionResult _$RobotoffQuestionResultFromJson(
         Map<String, dynamic> json) =>
     RobotoffQuestionResult(
       status: json['status'] as String?,
-      questions: RobotoffQuestion.fromJson(json['questions'] as List),
+      questions: (json['questions'] as List<dynamic>?)
+          ?.map((e) => RobotoffQuestion.fromJson(e as Map<String, dynamic>))
+          .toList(),
     );
 
 Map<String, dynamic> _$RobotoffQuestionResultToJson(
-    RobotoffQuestionResult instance) {
-  final val = <String, dynamic>{
-    'status': instance.status,
-  };
-
-  void writeNotNull(String key, dynamic value) {
-    if (value != null) {
-      val[key] = value;
-    }
+        RobotoffQuestionResult instance) =>
+    <String, dynamic>{
+      'status': instance.status,
+      'questions': instance.questions,
+    };
+
+RobotoffQuestion _$RobotoffQuestionFromJson(Map<String, dynamic> json) =>
+    RobotoffQuestion(
+      barcode: json['barcode'] as String?,
+      type: json['type'] as String?,
+      value: json['value'] as String?,
+      question: json['question'] as String?,
+      insightId: json['insight_id'] as String?,
+      insightType: _$enumDecodeNullable(
+          _$InsightTypeEnumMap, json['insight_type'],
+          unknownValue: InsightType.UNKNOWN),
+      imageUrl: json['source_image_url'] as String?,
+    );
+
+Map<String, dynamic> _$RobotoffQuestionToJson(RobotoffQuestion instance) =>
+    <String, dynamic>{
+      'barcode': instance.barcode,
+      'type': instance.type,
+      'value': instance.value,
+      'question': instance.question,
+      'insight_id': instance.insightId,
+      'insight_type': _$InsightTypeEnumMap[instance.insightType],
+      'source_image_url': instance.imageUrl,
+    };
+
+K _$enumDecode<K, V>(
+  Map<K, V> enumValues,
+  Object? source, {
+  K? unknownValue,
+}) {
+  if (source == null) {
+    throw ArgumentError(
+      'A value must be provided. Supported values: '
+      '${enumValues.values.join(', ')}',
+    );
   }
 
-  writeNotNull('questions', RobotoffQuestion.toJson(instance.questions));
-  return val;
+  return enumValues.entries.singleWhere(
+    (e) => e.value == source,
+    orElse: () {
+      if (unknownValue == null) {
+        throw ArgumentError(
+          '`$source` is not one of the supported values: '
+          '${enumValues.values.join(', ')}',
+        );
+      }
+      return MapEntry(unknownValue, enumValues.values.first);
+    },
+  ).key;
 }
+
+K? _$enumDecodeNullable<K, V>(
+  Map<K, V> enumValues,
+  dynamic source, {
+  K? unknownValue,
+}) {
+  if (source == null) {
+    return null;
+  }
+  return _$enumDecode<K, V>(enumValues, source, unknownValue: unknownValue);
+}
+
+const _$InsightTypeEnumMap = {
+  InsightType.INGREDIENT_SPELLCHECK: 'ingredient_spellcheck',
+  InsightType.PACKAGER_CODE: 'packager_code',
+  InsightType.LABEL: 'label',
+  InsightType.CATEGORY: 'category',
+  InsightType.PRODUCT_WEIGHT: 'product_weight',
+  InsightType.EXPIRATION_DATE: 'expiration_date',
+  InsightType.BRAND: 'brand',
+  InsightType.STORE: 'store',
+  InsightType.NUTRIENT: 'nutrient',
+  InsightType.UNDEFINED: 'undefined',
+  InsightType.UNKNOWN: 'UNKNOWN',
+};
diff --git a/lib/openfoodfacts.dart b/lib/openfoodfacts.dart
index ca917ef514..fe57bd72ea 100644
--- a/lib/openfoodfacts.dart
+++ b/lib/openfoodfacts.dart
@@ -444,8 +444,8 @@ class OpenFoodAPIClient {
   /// By default the query will hit the PROD DB
   static Future<RobotoffQuestionResult> getRobotoffQuestionsForProduct(
     String barcode,
-    String lang,
-    User user, {
+    String lang, {
+    User? user,
     int? count,
     QueryType? queryType,
   }) async {
diff --git a/test/api_getRobotoff_test.dart b/test/api_getRobotoff_test.dart
index f564feed6f..38e075b504 100644
--- a/test/api_getRobotoff_test.dart
+++ b/test/api_getRobotoff_test.dart
@@ -15,7 +15,7 @@ void main() {
           await OpenFoodAPIClient.getRobotoffQuestionsForProduct(
         '3274570800026',
         'en',
-        TestConstants.TEST_USER,
+        user: TestConstants.TEST_USER,
         count: 1,
       );
 
@@ -41,7 +41,7 @@ void main() {
           await OpenFoodAPIClient.getRobotoffQuestionsForProduct(
         '3274570800026',
         'fr',
-        TestConstants.TEST_USER,
+        user: TestConstants.TEST_USER,
       );
 
       if (result.status != 'no_questions') {
diff --git a/test/api_postRobotoff_test.dart b/test/api_postRobotoff_test.dart
index 8ab6c25922..7f556e0caa 100644
--- a/test/api_postRobotoff_test.dart
+++ b/test/api_postRobotoff_test.dart
@@ -11,8 +11,8 @@ void main() {
     test('get questions for Noix de Saint-Jacques EN and answer', () async {
       RobotoffQuestionResult result =
           await OpenFoodAPIClient.getRobotoffQuestionsForProduct(
-              '0080868000633', 'en', TestConstants.TEST_USER,
-              count: 1);
+              '0080868000633', 'en',
+              user: TestConstants.TEST_USER, count: 1);
 
       if (result.status == 'found') {
         Status postResult = await OpenFoodAPIClient.postInsightAnnotation(