diff --git a/src/treetrail/api_v1.py b/src/treetrail/api_v1.py
index 75573a9..41a1ce7 100644
--- a/src/treetrail/api_v1.py
+++ b/src/treetrail/api_v1.py
@@ -50,7 +50,7 @@ api_app = FastAPI(
     default_response_class=responses.ORJSONResponse,
 )
 
-re_findmimetype = re.compile('^data:(\S+);') # type: ignore
+re_findmimetype = re.compile(r'^data:(\S+);') # type: ignore
 
 attachment_types: dict[str, type[Tree] | type[Trail] | type[POI]] = {
     'tree': Tree,