diff --git a/openalexapi/ids.py b/openalexapi/ids.py
index 195f8e6..db9bbae 100644
--- a/openalexapi/ids.py
+++ b/openalexapi/ids.py
@@ -7,6 +7,7 @@
 
 
 class Ids(BaseModel):
+    openalex: Optional[str]
     doi: Optional[str]
     pmid: Optional[str]
     mag: Optional[str]