diff --git a/src/newsreader/news/collection/forms.py b/src/newsreader/news/collection/forms.py
index a8aac52..604500d 100644
--- a/src/newsreader/news/collection/forms.py
+++ b/src/newsreader/news/collection/forms.py
@@ -1,4 +1,5 @@
 from django import forms
+from django.core.exceptions import ValidationError
 from django.utils.safestring import mark_safe
 from django.utils.translation import gettext_lazy as _
 
@@ -6,15 +7,17 @@ import pytz
 
 from newsreader.news.collection.choices import RuleTypeChoices
 from newsreader.news.collection.models import CollectionRule
+from newsreader.news.collection.reddit import REDDIT_API_URL
 from newsreader.news.core.models import Category
 
 
 def get_reddit_help_text():
     return mark_safe(
-        "Only subreddits are supported. For example: "
-        "<a className='link' target='_blank' rel='noopener noreferrer'"
-        " href='https://reddit.com/r/aww'>https://www.reddit.com/r/aww</a>."
-        " Note that subreddit urls should NOT include 'www' because Reddit is picky."
+        "Only subreddits are supported"
+        " see the 'listings' section in <a className='link' target='_blank' rel='noopener noreferrer'"
+        " href='https://www.reddit.com/dev/api#section_listings'>the reddit API docs</a>."
+        " For example: <a className='link' target='_blank' rel='noopener noreferrer'"
+        " href='https://oauth.reddit.com/r/aww'>https://oauth.reddit.com/r/aww</a>"
     )
 
 
@@ -65,15 +68,19 @@ class SubRedditRuleForm(CollectionRuleForm):
 
     timezone = None
 
+    def clean_url(self):
+        url = self.cleaned_data["url"]
+
+        if not url.startswith(REDDIT_API_URL):
+            raise ValidationError(_("This does not look like an Reddit API URL"))
+
+        return url
+
     def save(self, commit=True):
         instance = super().save(commit=False)
 
         instance.type = RuleTypeChoices.subreddit
         instance.timezone = str(pytz.utc)
-        instance.user = self.user
-
-        if not instance.url.endswith(".json"):
-            instance.url = f"{instance.url}.json"
 
         if commit:
             instance.save()
diff --git a/src/newsreader/news/collection/tests/views/test_subreddit_views.py b/src/newsreader/news/collection/tests/views/test_subreddit_views.py
index a8de55e..0dff663 100644
--- a/src/newsreader/news/collection/tests/views/test_subreddit_views.py
+++ b/src/newsreader/news/collection/tests/views/test_subreddit_views.py
@@ -1,11 +1,12 @@
 from django.test import TestCase
 from django.urls import reverse
+from django.utils.translation import gettext as _
 
 import pytz
 
 from newsreader.news.collection.choices import RuleTypeChoices
 from newsreader.news.collection.models import CollectionRule
-from newsreader.news.collection.reddit import REDDIT_URL
+from newsreader.news.collection.reddit import REDDIT_API_URL, REDDIT_URL
 from newsreader.news.collection.tests.factories import SubredditFactory
 from newsreader.news.collection.tests.views.base import CollectionRuleViewTestCase
 from newsreader.news.core.tests.factories import CategoryFactory
@@ -17,7 +18,7 @@ class SubRedditCreateViewTestCase(CollectionRuleViewTestCase, TestCase):
 
         self.form_data = {
             "name": "new rule",
-            "url": "https://www.reddit.com/r/aww",
+            "url": f"{REDDIT_API_URL}/r/aww",
             "category": str(self.category.pk),
         }
 
@@ -31,12 +32,19 @@ class SubRedditCreateViewTestCase(CollectionRuleViewTestCase, TestCase):
         rule = CollectionRule.objects.get(name="new rule")
 
         self.assertEquals(rule.type, RuleTypeChoices.subreddit)
-        self.assertEquals(rule.url, "https://www.reddit.com/r/aww.json")
+        self.assertEquals(rule.url, f"{REDDIT_API_URL}/r/aww")
         self.assertEquals(rule.timezone, str(pytz.utc))
         self.assertEquals(rule.favicon, None)
         self.assertEquals(rule.category.pk, self.category.pk)
         self.assertEquals(rule.user.pk, self.user.pk)
 
+    def test_regular_reddit_url(self):
+        self.form_data.update(url=f"{REDDIT_URL}/r/aww")
+
+        response = self.client.post(self.url, self.form_data)
+
+        self.assertContains(response, _("This does not look like an Reddit API URL"))
+
 
 class SubRedditUpdateViewTestCase(CollectionRuleViewTestCase, TestCase):
     def setUp(self):
@@ -44,7 +52,7 @@ class SubRedditUpdateViewTestCase(CollectionRuleViewTestCase, TestCase):
 
         self.rule = SubredditFactory(
             name="Python",
-            url=f"{REDDIT_URL}/r/python.json",
+            url=f"{REDDIT_API_URL}/r/python.json",
             user=self.user,
             category=self.category,
             type=RuleTypeChoices.subreddit,
@@ -97,7 +105,7 @@ class SubRedditUpdateViewTestCase(CollectionRuleViewTestCase, TestCase):
         self.assertEquals(response.status_code, 404)
 
     def test_url_change(self):
-        self.form_data.update(name="aww", url=f"{REDDIT_URL}/r/aww")
+        self.form_data.update(name="aww", url=f"{REDDIT_API_URL}/r/aww")
 
         response = self.client.post(self.url, self.form_data)
 
@@ -106,8 +114,15 @@ class SubRedditUpdateViewTestCase(CollectionRuleViewTestCase, TestCase):
         rule = CollectionRule.objects.get(name="aww")
 
         self.assertEquals(rule.type, RuleTypeChoices.subreddit)
-        self.assertEquals(rule.url, f"{REDDIT_URL}/r/aww.json")
+        self.assertEquals(rule.url, f"{REDDIT_API_URL}/r/aww")
         self.assertEquals(rule.timezone, str(pytz.utc))
         self.assertEquals(rule.favicon, None)
         self.assertEquals(rule.category.pk, self.category.pk)
         self.assertEquals(rule.user.pk, self.user.pk)
+
+    def test_regular_reddit_url(self):
+        self.form_data.update(url=f"{REDDIT_URL}/r/aww")
+
+        response = self.client.post(self.url, self.form_data)
+
+        self.assertContains(response, _("This does not look like an Reddit API URL"))
diff --git a/src/newsreader/news/core/tests/factories.py b/src/newsreader/news/core/tests/factories.py
index 182db0e..520f940 100644
--- a/src/newsreader/news/core/tests/factories.py
+++ b/src/newsreader/news/core/tests/factories.py
@@ -3,7 +3,7 @@ import factory.fuzzy
 import pytz
 
 from newsreader.accounts.tests.factories import UserFactory
-from newsreader.news.collection.reddit import REDDIT_URL
+from newsreader.news.collection.reddit import REDDIT_API_URL
 from newsreader.news.core.models import Category, Post
 
 
@@ -38,7 +38,7 @@ class FeedPostFactory(PostFactory):
 
 
 class RedditPostFactory(PostFactory):
-    url = factory.fuzzy.FuzzyText(length=10, prefix=f"{REDDIT_URL}/")
+    url = factory.fuzzy.FuzzyText(length=10, prefix=f"{REDDIT_API_URL}/")
     rule = factory.SubFactory(
         "newsreader.news.collection.tests.factories.SubredditFactory"
     )