diff --git a/domain_manager.py b/domain_manager.py
index 955fd26..e5af142 100644
--- a/domain_manager.py
+++ b/domain_manager.py
@@ -463,7 +463,7 @@ class DomainManager:
         """
         try:
             # Validate inputs
-            if not username or not subdomain_name:
+            if not username or subdomain_name is None:
                 return {
                     'success': False,
                     'message': "Username and subdomain name are required",
@@ -478,7 +478,7 @@ class DomainManager:
                 return {'success': False, 'message': "Username cannot be represented as a DNS name", 'domain_data': None}
 
             # Hostnames are single labels below u-<username>.
-            if not self._is_valid_subdomain(subdomain_name):
+            if subdomain_name and not self._is_valid_subdomain(subdomain_name):
                 return {
                     'success': False,
                     'message': "Invalid subdomain name. Use only letters, numbers, and hyphens",
@@ -487,7 +487,7 @@ class DomainManager:
 
             # Construct domains
             user_domain = f"u-{username}.{self.base_domain}"
-            full_subdomain = f"{subdomain_name}.{user_domain}"
+            full_subdomain = f"{subdomain_name}.{user_domain}" if subdomain_name else user_domain
             namespace = self.ensure_user_namespace(username)
             if not namespace['success']:
                 return {'success': False, 'message': namespace['message'], 'domain_data': None}
@@ -631,7 +631,7 @@ class DomainManager:
     def delete_subdomain(self, username: str, subdomain_name: str) -> Dict:
         """Delete a subdomain"""
         try:
-            if not username or not subdomain_name:
+            if not username or subdomain_name is None:
                 return {
                     'success': False,
                     'message': "Username and subdomain name are required"
@@ -639,9 +639,14 @@ class DomainManager:
 
             username = username.lower().strip()
             subdomain_name = subdomain_name.lower().strip()
-            if not self._is_valid_username_label(username) or not self._is_valid_subdomain(subdomain_name):
+            if not self._is_valid_username_label(username):
                 return {'success': False, 'message': "Invalid username or subdomain"}
             user_domain = f"u-{username}.{self.base_domain}"
+            # Releasing the optional root claim must never remove the shared namespace DNS.
+            if not subdomain_name:
+                return {'success': True, 'message': f"Domain claim {user_domain} deleted"}
+            if not self._is_valid_subdomain(subdomain_name):
+                return {'success': False, 'message': "Invalid username or subdomain"}
             full_subdomain = f"{subdomain_name}.{user_domain}"
 
             # New namespaces use a shared wildcard in the parent zone. Do not
@@ -848,7 +853,7 @@ class DomainManager:
             subdomain_name = subdomain_name.lower().strip()
 
             # First validate the subdomain name
-            if not self._is_valid_subdomain(subdomain_name):
+            if subdomain_name and not self._is_valid_subdomain(subdomain_name):
                 return {
                     'available': False,
                     'message': f"Invalid subdomain name: {subdomain_name}"
diff --git a/routes/domains.py b/routes/domains.py
index 8213fcf..a057ca8 100644
--- a/routes/domains.py
+++ b/routes/domains.py
@@ -113,10 +113,10 @@ def create_domain_api():
             return jsonify({'error': 'Domain service not available'}), 503
 
         data = request.get_json()
-        subdomain = data.get('subdomain')
+        subdomain = '' if data.get('useUsernameDomain') is True else data.get('subdomain')
         server_id = data.get('serverId')
 
-        if not subdomain:
+        if subdomain is None:
             return jsonify({'error': 'Subdomain name required'}), 400
 
         # Check if subdomain is available
diff --git a/scripts/migrate_delegated_dns.py b/scripts/migrate_delegated_dns.py
index c0b682f..ae319e7 100644
--- a/scripts/migrate_delegated_dns.py
+++ b/scripts/migrate_delegated_dns.py
@@ -258,9 +258,9 @@ def apply_plan(api: DeSec, namespaces: Iterable[str], copies: List[Dict],
                 UPDATE user_domains
                    SET record_type = ?, ip_address = ?, ttl = 3600
                  WHERE COALESCE(is_custom, FALSE) = FALSE
-                   AND lower(full_domain) LIKE ? ESCAPE '!'
+                   AND (lower(full_domain) = ? OR lower(full_domain) LIKE ? ESCAPE '!')
                 """,
-                ('CNAME', api.base_domain, pattern),
+                ('CNAME', api.base_domain, f'{namespace}.{api.base_domain}', pattern),
             )
         connection.commit()
 
diff --git a/websocket_service.py b/websocket_service.py
index 38dddfd..0108e86 100644
--- a/websocket_service.py
+++ b/websocket_service.py
@@ -1383,12 +1383,12 @@ async def handle_create_domain(client_id, data):
 
     user_id = client_info['user_id']
     username = client_info['username']
-    subdomain_name = data.get('subdomain')
+    subdomain_name = '' if data.get('useUsernameDomain') is True else data.get('subdomain')
     server_id = data.get('serverId')
 
     logger.info(f"DEBUG: Creating domain for user {username}, subdomain: {subdomain_name}")
 
-    if not subdomain_name:
+    if subdomain_name is None:
         await send_message(client_id, {'type': 'error', 'error': 'Subdomain name required'})
         return
 
@@ -1398,7 +1398,7 @@ async def handle_create_domain(client_id, data):
         return
 
     # Validate subdomain name
-    if not domain_manager._is_valid_subdomain(subdomain_name):
+    if subdomain_name and not domain_manager._is_valid_subdomain(subdomain_name):
         await send_message(client_id, {'type': 'error', 'error': 'Invalid subdomain name. Use only lowercase letters, numbers, and hyphens (1-63 chars)'})
         return
 
@@ -1409,7 +1409,7 @@ async def handle_create_domain(client_id, data):
     try:
         # Check if subdomain is available (improved check)
         user_domain = f"u-{username}.{domain_manager.base_domain}"
-        full_subdomain = f"{subdomain_name}.{user_domain}"
+        full_subdomain = f"{subdomain_name}.{user_domain}" if subdomain_name else user_domain
 
         # Check if domain already exists in database
         with database_connection() as conn: