diff --git a/backend/src/backend/schedule_schemas.py b/backend/src/backend/schedule_schemas.py
index 31c7fbc..feb0fc4 100644
--- a/backend/src/backend/schedule_schemas.py
+++ b/backend/src/backend/schedule_schemas.py
@@ -103,7 +103,7 @@ class CreateScheduleNodeRequest(StrictModel):
     node_key: str = Field(
         min_length=1,
         max_length=64,
-        pattern=r"^[A-Za-z][A-Za-z0-9_-]*$",
+        pattern=r"^[A-Za-z0-9][A-Za-z0-9_-]*$",
     )
     node_name: str = Field(min_length=1, max_length=255)
     versions_id: str = Field(min_length=26, max_length=26)