diff --git a/bookwyrm/activitypub/__init__.py b/bookwyrm/activitypub/__init__.py
index 105e889b..931af0a0 100644
--- a/bookwyrm/activitypub/__init__.py
+++ b/bookwyrm/activitypub/__init__.py
@@ -4,6 +4,7 @@ import sys
 
 from .base_activity import ActivityEncoder, Image, PublicKey, Signature
 from .base_activity import Link, Mention
+from .base_activity import ActivitySerializerError
 from .note import Note, GeneratedNote, Article, Comment, Review, Quotation
 from .note import Tombstone
 from .interaction import Boost, Like