diff --git a/starter_packs/tests.py b/starter_packs/tests.py
index 491637b..1ac5559 100644
--- a/starter_packs/tests.py
+++ b/starter_packs/tests.py
@@ -3,6 +3,7 @@
 from model_bakery import baker
 
 from accounts.models import Account
+from starter_packs.models import StarterPackAccount
 
 
 class TestStarterPacks(TestCase):
@@ -173,6 +174,69 @@ def test_delete(self):
         self.assertIsNotNone(self.starter_pack.deleted_at)
 
 
+class TestToggleStarterPackAccount(TestCase):
+    @classmethod
+    def setUpTestData(cls):
+        cls.user = baker.make("auth.User")
+        baker.make("mastodon_auth.AccountAccess", user=cls.user)
+        cls.starter_pack = baker.make("starter_packs.StarterPack", created_by=cls.user)
+
+    def test_add_account(self):
+        account = baker.make("accounts.Account", discoverable=True)
+        self.client.force_login(self.user)
+        response = self.client.post(
+            reverse(
+                "toggle_account_to_starter_pack",
+                kwargs={"starter_pack_slug": self.starter_pack.slug, "account_id": account.id},
+            )
+        )
+        self.assertEqual(response.status_code, 200)
+        self.assertTrue(
+            StarterPackAccount.objects.filter(account_id=account.id, starter_pack_id=self.starter_pack.id).exists()
+        )
+
+    def test_remove_account(self):
+        account = baker.make("accounts.Account", discoverable=True)
+        self.client.force_login(self.user)
+        baker.make("starter_packs.StarterPackAccount", account=account, starter_pack=self.starter_pack)
+        response = self.client.post(
+            reverse(
+                "toggle_account_to_starter_pack",
+                kwargs={"starter_pack_slug": self.starter_pack.slug, "account_id": account.id},
+            )
+        )
+        self.assertEqual(response.status_code, 200)
+        self.assertFalse(
+            StarterPackAccount.objects.filter(account_id=account.id, starter_pack_id=self.starter_pack.id).exists()
+        )
+
+    def test_toggle_after_limit(self):
+        account = baker.make("accounts.Account", discoverable=True)
+        self.client.force_login(self.user)
+        # baker.make("starter_packs.StarterPackAccount", starter_pack=self.starter_pack, account=account)
+        baker.make("starter_packs.StarterPackAccount", starter_pack=self.starter_pack, _quantity=150)
+
+        self.assertEqual(self.starter_pack.starterpackaccount_set.count(), 150)
+        response = self.client.post(
+            reverse(
+                "toggle_account_to_starter_pack",
+                kwargs={"starter_pack_slug": self.starter_pack.slug, "account_id": account.id},
+            )
+        )
+        self.assertEqual(response.status_code, 200)
+
+        # Make sure we can delete even after the limit:
+        baker.make("starter_packs.StarterPackAccount", starter_pack=self.starter_pack, account=account)
+        self.assertEqual(self.starter_pack.starterpackaccount_set.count(), 151)
+        response = self.client.post(
+            reverse(
+                "toggle_account_to_starter_pack",
+                kwargs={"starter_pack_slug": self.starter_pack.slug, "account_id": account.id},
+            )
+        )
+        self.assertEqual(self.starter_pack.starterpackaccount_set.count(), 150)
+
+
 class TestShareStarterPack(TestCase):
     @classmethod
     def setUpTestData(cls):
diff --git a/starter_packs/views.py b/starter_packs/views.py
index df24d29..f382983 100644
--- a/starter_packs/views.py
+++ b/starter_packs/views.py
@@ -236,30 +236,32 @@ def create_starter_pack(request):
     )
 
 
+@transaction.atomic
 def toggle_account_to_starter_pack(request, starter_pack_slug, account_id):
     starter_pack = get_object_or_404(
         StarterPack, slug=starter_pack_slug, deleted_at__isnull=True, created_by=request.user
     )
-    if StarterPackAccount.objects.filter(starter_pack=starter_pack).count() > 150:
-        return render(
-            request,
-            "starter_pack_stats.html",
-            {
-                "starter_pack": starter_pack,
-                "num_accounts": StarterPackAccount.objects.filter(starter_pack=starter_pack).count(),
-                "error": "You have reached the maximum number of accounts in a starter pack.",
-            },
-        )
-    try:
-        StarterPackAccount.objects.create(
-            starter_pack=starter_pack,
-            account_id=account_id,
-        )
-    except IntegrityError:
+    if StarterPackAccount.objects.filter(starter_pack=starter_pack, account_id=account_id).exists():
         StarterPackAccount.objects.filter(
             starter_pack=starter_pack,
             account_id=account_id,
         ).delete()
+    else:
+        if StarterPackAccount.objects.filter(starter_pack=starter_pack).count() >= 150:
+            return render(
+                request,
+                "starter_pack_stats.html",
+                {
+                    "starter_pack": starter_pack,
+                    "num_accounts": StarterPackAccount.objects.filter(starter_pack=starter_pack).count(),
+                    "error": "You have reached the maximum number of accounts in a starter pack.",
+                },
+            )
+        StarterPackAccount.objects.create(
+            starter_pack=starter_pack,
+            account_id=account_id,
+        )
+
     return render(
         request,
         "starter_pack_stats.html",