diff --git a/API.md b/API.md
index da2edd6..9c87a13 100644
--- a/API.md
+++ b/API.md
@@ -1523,6 +1523,10 @@ One file together with its metadata posted to the site.
     "user":               <user>,
     "score":              <score>,
     "ownScore":           <own-score>,
+    "tagCount":           <tag-count>,
+    "favoriteCount":      <favorite-count>,
+    "commentCount":       <comment-count>,
+    "noteCount":          <note-count>,
     "featureCount":       <feature-count>,
     "lastFeatureTime":    <last-feature-time>,
     "favoritedBy":        <favorited-by>,
@@ -1582,6 +1586,10 @@ One file together with its metadata posted to the site.
 - `<score>`: the collective score (+1/-1 rating) of the given post.
 - `<own-score>`: the score (+1/-1 rating) of the given post by the
   authenticated user.
+- `<tag-count>`: how many tags the post is tagged with
+- `<favorite-count>`: how many users have the post in their favorites
+- `<comment-count>`: how many comments are filed under that post
+- `<note-count>`: how many notes the post has
 - `<feature-count>`: how many times has the post been featured.
 - `<last-feature-time>`: the last time the post was featured, formatted as per
   RFC 3339.
diff --git a/server/szurubooru/func/posts.py b/server/szurubooru/func/posts.py
index 99ff36d..498bad3 100644
--- a/server/szurubooru/func/posts.py
+++ b/server/szurubooru/func/posts.py
@@ -84,6 +84,10 @@ def serialize_post(post, authenticated_user, options=None):
             'user': lambda: users.serialize_user(post.user, authenticated_user),
             'score': lambda: post.score,
             'ownScore': lambda: scores.get_score(post, authenticated_user),
+            'tagCount': lambda: post.tag_count,
+            'favoriteCount': lambda: post.favorite_count,
+            'commentCount': lambda: post.comment_count,
+            'noteCount': lambda: post.note_count,
             'featureCount': lambda: post.feature_count,
             'lastFeatureTime': lambda: post.last_feature_time,
             'favoritedBy': lambda: [
diff --git a/server/szurubooru/tests/func/test_posts.py b/server/szurubooru/tests/func/test_posts.py
index 4d45a97..fa8abc4 100644
--- a/server/szurubooru/tests/func/test_posts.py
+++ b/server/szurubooru/tests/func/test_posts.py
@@ -96,13 +96,11 @@ def test_serialize_post(
         post.canvas_height = 300
         post.flags = ['loop']
         db.session.add(post)
-        post.comments = [
-            comment_factory(user=user_factory(name='commenter1')),
-            comment_factory(user=user_factory(name='commenter2')),
-        ]
 
         db.session.flush()
         db.session.add_all([
+            comment_factory(user=user_factory(name='commenter1'), post=post),
+            comment_factory(user=user_factory(name='commenter2'), post=post),
             db.PostFavorite(
                 post=post,
                 user=user_factory(name='fav1'),
@@ -150,6 +148,10 @@ def test_serialize_post(
         'user': 'post author',
         'score': 1,
         'ownScore': -1,
+        'tagCount': 2,
+        'favoriteCount': 1,
+        'commentCount': 2,
+        'noteCount': 0,
         'featureCount': 1,
         'lastFeatureTime': datetime.datetime(1999, 1, 1),
         'favoritedBy': ['fav1'],