diff --git a/g3w-admin/core/api/filters.py b/g3w-admin/core/api/filters.py
index e69aa8e12..91929455c 100644
--- a/g3w-admin/core/api/filters.py
+++ b/g3w-admin/core/api/filters.py
@@ -24,6 +24,7 @@
 from urllib.parse import unquote
 from core.utils.qgisapi import get_qgis_layer, get_qgis_features
 from qdjango.models import Layer
+import re
 
 class BaseFilterBackend():
     """Base class for QGIS request filters"""
@@ -283,7 +284,8 @@ def apply_filter(self, request, metadata_layer, qgis_feature_request, view):
             # field can be multiple separated by ','
             # i.e. $field=name|eq|Rome,state|eq|Italy
 
-            fields = suggest_value.split(',')
+            pattern = r',(?=(?:[^()]*\([^()]*\))*[^()]*$)'
+            fields = re.split(pattern, suggest_value)
 
             count = 0
             nfields = len(fields)
@@ -303,6 +305,8 @@ def apply_filter(self, request, metadata_layer, qgis_feature_request, view):
                         raise ParseError(
                             'Invalid field string supplied for parameter field')
 
+                # Make lowercase field_operator
+                field_operator = field_operator.lower()
                 if not self._is_valid_field(qgis_layer, field_name):
                     raise Exception(
                         f"{field_name} doesn't belong from layer {qgis_layer.name()}!")
@@ -335,6 +339,8 @@ def apply_filter(self, request, metadata_layer, qgis_feature_request, view):
                                 ),
                             )
                         )
+
+
                         qfr.combineFilterExpression(vr_single_search_expression)
                         features = get_qgis_features(relation_qgs_layer, qfr)
 
@@ -348,7 +354,7 @@ def apply_filter(self, request, metadata_layer, qgis_feature_request, view):
                         quoted_field_value = self._quote_value(
                             f'{pre_post_operator}{unquote(field_value)}{pre_post_operator}')
                     else:
-                        quoted_field_value = field_value
+                        quoted_field_value = unquote(field_value)
 
                     single_search_expression = '{field_name} {field_operator} {field_value}'.format(
                         field_name=self._quote_identifier(field_name),
diff --git a/g3w-admin/qdjango/tests/data/geodata/qgis_widget_test_data.gpkg b/g3w-admin/qdjango/tests/data/geodata/qgis_widget_test_data.gpkg
index 1ba1d58b4..de09d6c50 100644
Binary files a/g3w-admin/qdjango/tests/data/geodata/qgis_widget_test_data.gpkg and b/g3w-admin/qdjango/tests/data/geodata/qgis_widget_test_data.gpkg differ
diff --git a/g3w-admin/qdjango/tests/test_api.py b/g3w-admin/qdjango/tests/test_api.py
index 618aa66d7..11d44306d 100644
--- a/g3w-admin/qdjango/tests/test_api.py
+++ b/g3w-admin/qdjango/tests/test_api.py
@@ -1576,6 +1576,33 @@ def test_server_filters_combination_api(self):
 
         self.assertEqual(resp['vector']['count'], total_count)
 
+        qgs_request = QgsFeatureRequest()
+        qgs_request.setFilterExpression('"ISO2_CODE" IN (\'IT\', \'FR\')')
+        total_count = len([f for f in qgis_layer.getFeatures(qgs_request)])
+
+        # For IN comparator
+        # .................
+        # Test http 'get' method:
+        resp = json.loads(self._testApiCall('core-vector-api',
+                                            ['data', 'qdjango', self.project310.instance.pk,
+                                             cities.qgs_layer_id],
+                                            {
+                                                'field': 'ISO2_CODE|in|(\'IT\', \'FR\')'
+                                            }).content)
+
+        self.assertEqual(resp['vector']['count'], total_count)
+
+        # Test http 'post' method:
+        resp = json.loads(self._testApiCall('core-vector-api',
+                                            ['data', 'qdjango', self.project310.instance.pk,
+                                             cities.qgs_layer_id],
+                                            {
+                                                'field': 'ISO2_CODE|in|(\'IT\', \'FR\')'
+                                            },
+                                            method='post').content)
+
+        self.assertEqual(resp['vector']['count'], total_count)
+
         qgs_request = QgsFeatureRequest()
         qgs_request.setFilterExpression(
             '"ISO2_CODE" = \'IT\' OR "ISO2_CODE" = \'FR\'')