diff --git a/.github/workflows/test-only.yml b/.github/workflows/test-only.yml
index a7de9c7b..9acfb3f8 100644
--- a/.github/workflows/test-only.yml
+++ b/.github/workflows/test-only.yml
@@ -36,6 +36,8 @@ jobs:
         run: |         
           # Build a changedetection.io container and start testing inside
           docker build . -t test-changedetectionio
+          # Debug info
+          docker run test-changedetectionio  bash -c 'pip list'
 
       - name: Spin up ancillary SMTP+Echo message test server
         run: |
@@ -44,7 +46,6 @@ jobs:
 
       - name: Test built container with pytest
         run: |
-          
           # Unit tests
           docker run test-changedetectionio  bash -c 'python3 -m unittest changedetectionio.tests.unit.test_notification_diff'
           
diff --git a/changedetectionio/api/api_v1.py b/changedetectionio/api/api_v1.py
index f81b1d58..783827ca 100644
--- a/changedetectionio/api/api_v1.py
+++ b/changedetectionio/api/api_v1.py
@@ -1,3 +1,6 @@
+import os
+from distutils.util import strtobool
+
 from flask_expects_json import expects_json
 from changedetectionio import queuedWatchMetaData
 from flask_restful import abort, Resource
@@ -209,7 +212,9 @@ class CreateWatch(Resource):
         json_data = request.get_json()
         url = json_data['url'].strip()
 
-        if not validators.url(json_data['url'].strip()):
+        # If hosts that only contain alphanumerics are allowed ("localhost" for example)
+        allow_simplehost = not strtobool(os.getenv('BLOCK_SIMPLEHOSTS', 'False'))
+        if not validators.url(url, simple_host=allow_simplehost):
             return "Invalid or unsupported URL", 400
 
         if json_data.get('proxy'):
diff --git a/changedetectionio/forms.py b/changedetectionio/forms.py
index 7199b445..4725b181 100644
--- a/changedetectionio/forms.py
+++ b/changedetectionio/forms.py
@@ -1,5 +1,6 @@
 import os
 import re
+from distutils.util import strtobool
 
 from wtforms import (
     BooleanField,
@@ -257,9 +258,10 @@ class validateURL(object):
 
     def __call__(self, form, field):
         import validators
-
+        # If hosts that only contain alphanumerics are allowed ("localhost" for example)
+        allow_simplehost = not strtobool(os.getenv('BLOCK_SIMPLEHOSTS', 'False'))
         try:
-            validators.url(field.data.strip())
+            validators.url(field.data.strip(), simple_host=allow_simplehost)
         except validators.ValidationFailure:
             message = field.gettext('\'%s\' is not a valid URL.' % (field.data.strip()))
             raise ValidationError(message)
diff --git a/requirements.txt b/requirements.txt
index 9c09aca3..6fec3029 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,7 +10,8 @@ flask~=2.0
 inscriptis~=2.2
 pytz
 timeago~=1.0
-validators
+validators~=0.21
+
 
 # Set these versions together to avoid a RequestsDependencyWarning
 # >= 2.26 also adds Brotli support if brotli is installed