diff --git a/src/fontra/core/protocols.py b/src/fontra/core/protocols.py
index fc0cf8e7b..6af196c0a 100644
--- a/src/fontra/core/protocols.py
+++ b/src/fontra/core/protocols.py
@@ -76,7 +76,7 @@ class ProjectManager(Protocol):
     async def close(self) -> None:
         ...
 
-    async def authorize(self, request: web.Request) -> str:
+    async def authorize(self, request: web.Request) -> str | None:
         ...
 
     async def projectAvailable(self, path: str, token: str) -> bool: