diff --git a/api/tests.py b/api/tests.py
index 9b60202875..1ea31d542b 100644
--- a/api/tests.py
+++ b/api/tests.py
@@ -205,9 +205,14 @@ def test_wrap_all_entities(self):
         self.assertTrue('<a class ="refLink"' in data['versions'][0]['text'][3])
         self.assertTrue('<a href="/topics' in data['versions'][0]['text'][8])
 
-    def text_text_only(self):
+    def test_text_only(self):
         response = c.get(f"/api/v3/texts/Shulchan_Arukh%2C_Orach_Chayim.1:1?return_format=text_only")
         self.assertEqual(200, response.status_code)
         data = json.loads(response.content)
         self.assertFalse('<' in data['versions'][0]['text'])
 
+    def test_error_return_format(self):
+        response = c.get(f"/api/v3/texts/Shulchan_Arukh%2C_Orach_Chayim.1:1?return_format=not_valid")
+        self.assertEqual(400, response.status_code)
+        data = json.loads(response.content)
+        self.assertEqual(data['error'], "return_format should be one of those formats: ['default', 'wrap_all_entities', 'text_only'].")
diff --git a/api/views.py b/api/views.py
index ec2f67077f..c6e0beca82 100644
--- a/api/views.py
+++ b/api/views.py
@@ -7,6 +7,8 @@
 
 class Text(View):
 
+    RETURN_FORMATS = ['default', 'wrap_all_entities', 'text_only']
+
     def dispatch(self, request, *args, **kwargs):
         try:
             self.oref = Ref.instantiate_ref_with_legacy_parse_fallback(kwargs['tref'])
@@ -48,6 +50,8 @@ def get(self, request, *args, **kwargs):
         versions_params = [self.split_piped_params(param_str) for param_str in versions_params]
         fill_in_missing_segments = request.GET.get('fill_in_missing_segments', False)
         return_format = request.GET.get('return_format', 'default')
+        if return_format not in self.RETURN_FORMATS:
+            return jsonResponse({'error': f'return_format should be one of those formats: {self.RETURN_FORMATS}.'}, status=400)
         text_manager = TextManager(self.oref, versions_params, fill_in_missing_segments, return_format)
         data = text_manager.get_versions_for_query()
         data = self._handle_warnings(data)