diff --git a/selfprivacy_api/graphql/common_types/service.py b/selfprivacy_api/graphql/common_types/service.py
index 367ef6a..fb6c972 100644
--- a/selfprivacy_api/graphql/common_types/service.py
+++ b/selfprivacy_api/graphql/common_types/service.py
@@ -175,6 +175,7 @@ class Service:
     is_movable: bool
     is_required: bool
     is_enabled: bool
+    is_installed: bool
     can_be_backed_up: bool
     backup_description: str
     status: ServiceStatusEnum
@@ -232,6 +233,7 @@ def service_to_graphql_service(service: ServiceInterface) -> Service:
         is_movable=service.is_movable(),
         is_required=service.is_required(),
         is_enabled=service.is_enabled(),
+        is_installed=service.is_installed(),
         can_be_backed_up=service.can_be_backed_up(),
         backup_description=service.get_backup_description(),
         status=ServiceStatusEnum(service.get_status().value),
diff --git a/selfprivacy_api/services/service.py b/selfprivacy_api/services/service.py
index 007070c..114d76c 100644
--- a/selfprivacy_api/services/service.py
+++ b/selfprivacy_api/services/service.py
@@ -146,6 +146,16 @@ class Service(ABC):
         with ReadUserData() as user_data:
             return user_data.get("modules", {}).get(name, {}).get("enable", False)
 
+    @classmethod
+    def is_installed(cls) -> bool:
+        """
+        `True` if the service is installed.
+        `False` if there is no module data in user data
+        """
+        name = cls.get_id()
+        with ReadUserData() as user_data:
+            return user_data.get("modules", {}).get(name, {}) != {}
+
     @staticmethod
     @abstractmethod
     def get_status() -> ServiceStatus: