diff --git a/bookwyrm/activitypub/base_activity.py b/bookwyrm/activitypub/base_activity.py
index 54cc4679d..5f16906b7 100644
--- a/bookwyrm/activitypub/base_activity.py
+++ b/bookwyrm/activitypub/base_activity.py
@@ -76,6 +76,12 @@ class ActivityObject:
         if not isinstance(self, model.activity_serializer):
             raise TypeError('Wrong activity type for model')
 
+        # check for an existing instance
+        try:
+            return model.objects.get(remote_id=self.id)
+        except model.DoesNotExist:
+            pass
+
         model_fields = [m.name for m in model._meta.get_fields()]
         mapped_fields = {}
 
diff --git a/bookwyrm/activitypub/interaction.py b/bookwyrm/activitypub/interaction.py
index 2da005875..752b2fe3f 100644
--- a/bookwyrm/activitypub/interaction.py
+++ b/bookwyrm/activitypub/interaction.py
@@ -8,7 +8,7 @@ from .base_activity import ActivityObject
 class Like(ActivityObject):
     ''' a user faving an object '''
     actor: str
-    object: ActivityObject
+    object: str
     type: str = 'Like'
 
 
@@ -16,5 +16,5 @@ class Like(ActivityObject):
 class Boost(ActivityObject):
     ''' boosting a status '''
     actor: str
-    object: ActivityObject
+    object: str
     type: str = 'Announce'
diff --git a/bookwyrm/incoming.py b/bookwyrm/incoming.py
index c6a22caa1..134c54845 100644
--- a/bookwyrm/incoming.py
+++ b/bookwyrm/incoming.py
@@ -68,6 +68,7 @@ def shared_inbox(request):
         'Undo': {
             'Follow': handle_unfollow,
             'Like': handle_unfavorite,
+            'Announce': handle_unboost,
         },
         'Update': {
             'Person': handle_update_user,
@@ -267,48 +268,50 @@ def handle_delete_status(activity):
 @app.task
 def handle_favorite(activity):
     ''' approval of your good good post '''
-    fav = activitypub.Like(**activity['object'])
-    # raises ValueError in to_model if a foreign key could not be resolved in
+    fav = activitypub.Like(**activity)
 
     liker = get_or_create_remote_user(activity['actor'])
     if liker.local:
         return
 
-    status = fav.to_model(models.Favorite)
+    fav = fav.to_model(models.Favorite)
 
     status_builder.create_notification(
-        status.user,
+        fav.status.user,
         'FAVORITE',
         related_user=liker,
-        related_status=status,
+        related_status=fav.status,
     )
 
 
 @app.task
 def handle_unfavorite(activity):
     ''' approval of your good good post '''
-    like = activitypub.Like(**activity['object'])
-    fav = models.Favorite.objects.filter(remote_id=like.id).first()
-
-    fav.delete()
+    like = activitypub.Like(**activity['object']).to_model(models.Favorite)
+    like.delete()
 
 
 @app.task
 def handle_boost(activity):
     ''' someone gave us a boost! '''
-    status_id = activity['object'].split('/')[-1]
-    status = models.Status.objects.get(id=status_id)
-    booster = get_or_create_remote_user(activity['actor'])
+    boost = activitypub.Boost(**activity).to_model(models.Boost)
 
-    if not booster.local:
-        status_builder.create_boost_from_activity(booster, activity)
+    if not boost.user.local:
+        status_builder.create_notification(
+            boost.boosted_status.user,
+            'BOOST',
+            related_user=boost.user,
+            related_status=boost.boosted_status,
+        )
 
-    status_builder.create_notification(
-        status.user,
-        'BOOST',
-        related_user=booster,
-        related_status=status,
-    )
+
+@app.task
+def handle_unboost(activity):
+    ''' someone gave us a boost! '''
+    boost = models.Boost.objects.filter(remote_id=activity['object']['id']).first()
+    if not boost:
+        return
+    status_builder.delete_status(boost)
 
 
 @app.task
diff --git a/bookwyrm/models/status.py b/bookwyrm/models/status.py
index fa80fecb9..f9a217e7f 100644
--- a/bookwyrm/models/status.py
+++ b/bookwyrm/models/status.py
@@ -76,8 +76,8 @@ class Status(OrderedCollectionPageMixin, BookWyrmModel):
         return tags
 
     shared_mappings = [
+        ActivityMapping('url', 'remote_id', lambda x: None),
         ActivityMapping('id', 'remote_id'),
-        ActivityMapping('url', 'remote_id'),
         ActivityMapping('inReplyTo', 'reply_parent'),
         ActivityMapping('published', 'published_date'),
         ActivityMapping('attributedTo', 'user'),
@@ -136,6 +136,7 @@ class Status(OrderedCollectionPageMixin, BookWyrmModel):
         return ActivitypubMixin.to_activity(self, pure=pure)
 
     def save(self, *args, **kwargs):
+        ''' update user active time '''
         self.user.last_active_date = timezone.now()
         self.user.save()
         super().save(*args, **kwargs)
@@ -240,6 +241,7 @@ class Favorite(ActivitypubMixin, BookWyrmModel):
     activity_serializer = activitypub.Like
 
     def save(self, *args, **kwargs):
+        ''' update user active time '''
         self.user.last_active_date = timezone.now()
         self.user.save()
         super().save(*args, **kwargs)
@@ -285,6 +287,7 @@ class ReadThrough(BookWyrmModel):
         null=True)
 
     def save(self, *args, **kwargs):
+        ''' update user active time '''
         self.user.last_active_date = timezone.now()
         self.user.save()
         super().save(*args, **kwargs)