diff --git a/src/schemas.py b/src/schemas.py
index 2dc8ab1..0dc11f4 100644
--- a/src/schemas.py
+++ b/src/schemas.py
@@ -21,11 +21,11 @@ class SampleSchema(ma.Schema):
     """
     Parameters:
      - date (date)
-     - device_id (str)
+     - device_id (int)
     """
 
     date = fields.DateTime(required=True)
-    device_id = fields.Str(required=True)
+    device_id = fields.Integer(required=True)
 
 
 class SampleMetadataSchema(ma.SQLAlchemyAutoSchema):