diff --git a/CHANGELOG.md b/CHANGELOG.md
index 27ffc08391..4d186aee0b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Unify breadcrumbs behaviour with other Grafana Apps and main core ([#1906](https://github.com/grafana/oncall/issues/1906))
 
+### Fixed
+
+- Fix regression in public actions endpoint handling user field by @mderynck ([#3053](https://github.com/grafana/oncall/pull/3053))
+
 ## v1.3.38 (2023-09-19)
 
 ### Fixed
diff --git a/engine/apps/public_api/serializers/action.py b/engine/apps/public_api/serializers/action.py
index 853369f8b8..d9af4ff922 100644
--- a/engine/apps/public_api/serializers/action.py
+++ b/engine/apps/public_api/serializers/action.py
@@ -9,7 +9,7 @@
 
 class ActionCreateSerializer(WebhookCreateSerializer):
     team_id = TeamPrimaryKeyRelatedField(allow_null=True, default=CurrentTeamDefault(), source="team")
-    user = serializers.CharField(required=False, source="username")
+    user = serializers.CharField(required=False, source="username", allow_null=True, allow_blank=True)
     trigger_type = WebhookTriggerTypeField(required=False)
     forward_whole_payload = serializers.BooleanField(required=False, source="forward_all")
 
@@ -23,7 +23,6 @@ class Meta:
             "team_id",
             "user",
             "data",
-            "user",
             "password",
             "authorization_header",
             "trigger_template",
@@ -37,6 +36,12 @@ class Meta:
         extra_kwargs = {
             "name": {"required": True, "allow_null": False, "allow_blank": False},
             "url": {"required": True, "allow_null": False, "allow_blank": False},
+            "data": {"required": False, "allow_null": True, "allow_blank": True},
+            "password": {"required": False, "allow_null": True, "allow_blank": True},
+            "authorization_header": {"required": False, "allow_null": True, "allow_blank": True},
+            "trigger_template": {"required": False, "allow_null": True, "allow_blank": True},
+            "headers": {"required": False, "allow_null": True, "allow_blank": True},
+            "integration_filter": {"required": False, "allow_null": True},
         }
 
         validators = [UniqueTogetherValidator(queryset=Webhook.objects.all(), fields=["name", "organization"])]
@@ -51,13 +56,13 @@ class Meta(ActionCreateSerializer.Meta):
         extra_kwargs = {
             "name": {"required": False, "allow_null": False, "allow_blank": False},
             "is_webhook_enabled": {"required": False, "allow_null": False},
-            "user": {"required": False, "allow_null": True, "allow_blank": False},
-            "password": {"required": False, "allow_null": True, "allow_blank": False},
-            "authorization_header": {"required": False, "allow_null": True, "allow_blank": False},
-            "trigger_template": {"required": False, "allow_null": True, "allow_blank": False},
-            "headers": {"required": False, "allow_null": True, "allow_blank": False},
+            "user": {"required": False, "allow_null": True, "allow_blank": True},
+            "password": {"required": False, "allow_null": True, "allow_blank": True},
+            "authorization_header": {"required": False, "allow_null": True, "allow_blank": True},
+            "trigger_template": {"required": False, "allow_null": True, "allow_blank": True},
+            "headers": {"required": False, "allow_null": True, "allow_blank": True},
             "url": {"required": False, "allow_null": False, "allow_blank": False},
-            "data": {"required": False, "allow_null": True, "allow_blank": False},
+            "data": {"required": False, "allow_null": True, "allow_blank": True},
             "forward_whole_payload": {"required": False, "allow_null": False},
             "http_method": {"required": False, "allow_null": False, "allow_blank": False},
             "integration_filter": {"required": False, "allow_null": True},
diff --git a/engine/apps/public_api/serializers/webhooks.py b/engine/apps/public_api/serializers/webhooks.py
index 44a92634f8..70f3d6a420 100644
--- a/engine/apps/public_api/serializers/webhooks.py
+++ b/engine/apps/public_api/serializers/webhooks.py
@@ -78,6 +78,14 @@ class Meta:
             "name": {"required": True, "allow_null": False, "allow_blank": False},
             "url": {"required": True, "allow_null": False, "allow_blank": False},
             "http_method": {"required": True, "allow_null": False, "allow_blank": False},
+            "username": {"required": False, "allow_null": True, "allow_blank": True},
+            "password": {"required": False, "allow_null": True, "allow_blank": True},
+            "authorization_header": {"required": False, "allow_null": True, "allow_blank": True},
+            "trigger_template": {"required": False, "allow_null": True, "allow_blank": True},
+            "headers": {"required": False, "allow_null": True, "allow_blank": True},
+            "data": {"required": False, "allow_null": True, "allow_blank": True},
+            "forward_all": {"required": False, "allow_null": False},
+            "integration_filter": {"required": False, "allow_null": True},
         }
 
         validators = [UniqueTogetherValidator(queryset=Webhook.objects.all(), fields=["name", "organization"])]
@@ -157,13 +165,13 @@ class Meta(WebhookCreateSerializer.Meta):
         extra_kwargs = {
             "name": {"required": False, "allow_null": False, "allow_blank": False},
             "is_webhook_enabled": {"required": False, "allow_null": False},
-            "username": {"required": False, "allow_null": True, "allow_blank": False},
-            "password": {"required": False, "allow_null": True, "allow_blank": False},
-            "authorization_header": {"required": False, "allow_null": True, "allow_blank": False},
-            "trigger_template": {"required": False, "allow_null": True, "allow_blank": False},
-            "headers": {"required": False, "allow_null": True, "allow_blank": False},
+            "username": {"required": False, "allow_null": True, "allow_blank": True},
+            "password": {"required": False, "allow_null": True, "allow_blank": True},
+            "authorization_header": {"required": False, "allow_null": True, "allow_blank": True},
+            "trigger_template": {"required": False, "allow_null": True, "allow_blank": True},
+            "headers": {"required": False, "allow_null": True, "allow_blank": True},
             "url": {"required": False, "allow_null": False, "allow_blank": False},
-            "data": {"required": False, "allow_null": True, "allow_blank": False},
+            "data": {"required": False, "allow_null": True, "allow_blank": True},
             "forward_all": {"required": False, "allow_null": False},
             "http_method": {"required": False, "allow_null": False, "allow_blank": False},
             "integration_filter": {"required": False, "allow_null": True},
diff --git a/engine/apps/public_api/tests/test_custom_actions.py b/engine/apps/public_api/tests/test_custom_actions.py
index f763b7a373..62504c38d0 100644
--- a/engine/apps/public_api/tests/test_custom_actions.py
+++ b/engine/apps/public_api/tests/test_custom_actions.py
@@ -160,17 +160,44 @@ def test_get_custom_action(
 
 
 @pytest.mark.django_db
-def test_create_custom_action(make_organization_and_user_with_token):
+@pytest.mark.parametrize(
+    "data",
+    [
+        (
+            {
+                "name": "Test outgoing webhook",
+                "url": "https://example.com",
+            }
+        ),
+        (
+            {
+                "name": "Test outgoing webhook",
+                "url": "https://example.com",
+                "user": None,
+                "password": None,
+                "data": None,
+                "authorization_header": None,
+                "forward_whole_payload": True,
+            }
+        ),
+        (
+            {
+                "name": "Test outgoing webhook",
+                "url": "https://example.com",
+                "user": "",
+                "password": "",
+                "data": "",
+                "authorization_header": "",
+                "forward_whole_payload": True,
+            }
+        ),
+    ],
+)
+def test_create_custom_action(make_organization_and_user_with_token, data):
     organization, user, token = make_organization_and_user_with_token()
     client = APIClient()
 
     url = reverse("api-public:actions-list")
-
-    data = {
-        "name": "Test outgoing webhook",
-        "url": "https://example.com",
-    }
-
     response = client.post(url, data=data, format="json", HTTP_AUTHORIZATION=f"{token}")
 
     custom_action = Webhook.objects.get(public_primary_key=response.data["id"])
diff --git a/engine/apps/public_api/tests/test_webhooks.py b/engine/apps/public_api/tests/test_webhooks.py
index 0e6feb3fbe..efe7870f05 100644
--- a/engine/apps/public_api/tests/test_webhooks.py
+++ b/engine/apps/public_api/tests/test_webhooks.py
@@ -163,6 +163,45 @@ def test_create_webhook(make_organization_and_user_with_token):
     assert response.data == expected_result
 
 
+@pytest.mark.django_db
+@pytest.mark.parametrize(
+    "optional_value",
+    [
+        None,
+        "",
+    ],
+)
+def test_create_webhook_optional_fields(make_organization_and_user_with_token, optional_value):
+    organization, user, token = make_organization_and_user_with_token()
+    client = APIClient()
+
+    url = reverse("api-public:webhooks-list")
+
+    data = {
+        "name": "Test outgoing webhook with nested data",
+        "url": "https://example.com",
+        "http_method": "POST",
+        "trigger_type": "acknowledge",
+        "data": optional_value,
+        "username": optional_value,
+        "password": optional_value,
+        "authorization_header": optional_value,
+        "trigger_template": optional_value,
+        "headers": optional_value,
+        "forward_all": True,
+        "is_webhook_enabled": True,
+        "integration_filter": optional_value,
+    }
+
+    response = client.post(url, data=data, format="json", HTTP_AUTHORIZATION=f"{token}")
+    webhook = Webhook.objects.get(public_primary_key=response.data["id"])
+
+    expected_result = _get_expected_result(webhook)
+
+    assert response.status_code == status.HTTP_201_CREATED
+    assert response.json() == expected_result
+
+
 @pytest.mark.django_db
 def test_create_webhook_nested_data(make_organization_and_user_with_token):
     organization, user, token = make_organization_and_user_with_token()