diff --git a/src/newsreader/news/collection/tests/endpoints/rule/list/tests.py b/src/newsreader/news/collection/tests/endpoints/rule/list/tests.py
index 5a34dbc..2ae3810 100644
--- a/src/newsreader/news/collection/tests/endpoints/rule/list/tests.py
+++ b/src/newsreader/news/collection/tests/endpoints/rule/list/tests.py
@@ -202,7 +202,7 @@ class NestedRuleListViewTestCase(TestCase):
 
         for post in data["results"]:
             with self.subTest(post=post):
-                self.assertEqual(post["rule"], rule.pk)
+                self.assertEqual(post["rule"]["id"], rule.pk)
 
     def test_unread_posts(self):
         rule = FeedFactory.create(user=self.user)
diff --git a/src/newsreader/news/core/serializers.py b/src/newsreader/news/core/serializers.py
index d77469a..c375dde 100644
--- a/src/newsreader/news/core/serializers.py
+++ b/src/newsreader/news/core/serializers.py
@@ -10,7 +10,7 @@ class PostSerializer(serializers.ModelSerializer):
     )
     remoteIdentifier = serializers.CharField(source="remote_identifier", required=False)
 
-    rule = RuleSerializer()
+    rule = RuleSerializer(read_only=True)
 
     class Meta:
         model = Post
diff --git a/src/newsreader/news/core/tests/endpoints/category/list/tests.py b/src/newsreader/news/core/tests/endpoints/category/list/tests.py
index c822950..65f4433 100644
--- a/src/newsreader/news/core/tests/endpoints/category/list/tests.py
+++ b/src/newsreader/news/core/tests/endpoints/category/list/tests.py
@@ -510,8 +510,8 @@ class NestedCategoryPostView(TestCase):
         self.assertEqual(response.status_code, 200)
         self.assertEqual(len(data["results"]), 2)
 
-        self.assertEqual(posts[0]["rule"], guardian_rule.pk)
-        self.assertEqual(posts[1]["rule"], guardian_rule.pk)
+        self.assertEqual(posts[0]["rule"]["id"], guardian_rule.pk)
+        self.assertEqual(posts[1]["rule"]["id"], guardian_rule.pk)
 
     def test_unread_posts(self):
         category = CategoryFactory.create(user=self.user)
diff --git a/src/newsreader/news/core/tests/endpoints/post/detail/tests.py b/src/newsreader/news/core/tests/endpoints/post/detail/tests.py
index 92444cc..295f92f 100644
--- a/src/newsreader/news/core/tests/endpoints/post/detail/tests.py
+++ b/src/newsreader/news/core/tests/endpoints/post/detail/tests.py
@@ -111,6 +111,7 @@ class PostDetailViewTestCase(TestCase):
             data=json.dumps({"title": "This title is very accurate"}),
             content_type="application/json",
         )
+
         data = response.json()
 
         self.assertEqual(response.status_code, 200)