diff --git a/optimade/utils.py b/optimade/utils.py
index 418c712b8..e315ae485 100644
--- a/optimade/utils.py
+++ b/optimade/utils.py
@@ -10,7 +10,6 @@
 from traceback import print_exc
 from typing import TYPE_CHECKING, Optional
 
-import bson.json_util
 from requests.exceptions import SSLError
 
 if TYPE_CHECKING:
@@ -35,6 +34,8 @@ def insert_from_jsonl(jsonl_path: Path) -> None:
     """
     from collections import defaultdict
 
+    import bson.json_util
+
     from optimade.server.routers import ENTRY_COLLECTIONS
 
     batch = defaultdict(list)