diff --git a/README.rst b/README.rst
index 72213cb..92f1c3e 100644
--- a/README.rst
+++ b/README.rst
@@ -62,6 +62,29 @@ This packages are needed to make the email complient for all the email clients.
     npm install --save inline-css
     npm install --save html-minifier
 
+
+Add *'mail_editor'* to the installed apps:
+
+.. code:: python
+
+    # settings.py
+
+    INSTALLED_APPS = [
+        ...
+        'mail_editor',
+        'ckeditor',
+        ...
+    ]
+
+Add the urls:
+
+.. code:: python
+
+    # urls.py
+
+    url(r'^mail-editor/', include('mail_editor.urls', namespace='mail_editor')),
+
+
 Using the template
 --------------------
 
diff --git a/mail_editor/mail_template.py b/mail_editor/mail_template.py
index 2dfd4a2..b8f6166 100644
--- a/mail_editor/mail_template.py
+++ b/mail_editor/mail_template.py
@@ -63,14 +63,14 @@ def check_variables(self, template, field):
             message = _('These variables are required, but missing: {vars}').format(
                 vars=self._format_vars(missing_vars)
             )
-            raise ValidationError({field: message}, code=self.code)
+            raise ValidationError(params={field: message}, message=message, code=self.code)
 
         unexpected_vars = variables_seen - required_vars - optional_vars
         if unexpected_vars:
             message = _('These variables are present, but unexpected: {vars}').format(
                 vars=self._format_vars(unexpected_vars)
             )
-            raise ValidationError({field: message}, code=self.code)
+            raise ValidationError(params={field: message}, message=message, code=self.code)
 
     def _format_vars(self, variables):
         return ', '.join('{{{{ {} }}}}'.format(var) for var in variables)
@@ -90,8 +90,9 @@ def validate_template(mail_template):
 
     if errors:
         main_error = errors[0]
-        for error in errors[1:]:
-            error.update_error_dict(main_error.error_dict)
+        if len(errors) > 1:
+            for error in errors[1:]:
+                main_error.update_error_dict(error.error_dict)
         raise main_error
 
 
diff --git a/mail_editor/templates/admin/mail_editor/change_form.html b/mail_editor/templates/admin/mail_editor/change_form.html
new file mode 100644
index 0000000..7fc0bec
--- /dev/null
+++ b/mail_editor/templates/admin/mail_editor/change_form.html
@@ -0,0 +1,15 @@
+{% extends "admin/change_form.html" %}
+
+
+{% block extrahead %}
+{{ block.super }}
+<script>
+    django.jQuery(document).ready(function() {
+        $('#id_template_type').change(function(){
+            $.get('{% url "mail_editor:template_variables" original.template_type %}', function(data, textStatus, jqXHR) {
+                $('.field-get_variable_help_text').innerHTML = data
+            });
+        });
+    });
+</script>
+{% endblock %}
diff --git a/mail_editor/urls.py b/mail_editor/urls.py
new file mode 100644
index 0000000..15adb6f
--- /dev/null
+++ b/mail_editor/urls.py
@@ -0,0 +1,10 @@
+from django.conf.urls import url
+
+from .views import TemplateVariableView
+
+# Add app_name to support django 2.0+
+app_name = "mail_editor"
+
+urlpatterns = [
+    url(r'^(?P<template_type>[-\w]+)/$', TemplateVariableView.as_view(), name='template_variables'),
+]
diff --git a/mail_editor/views.py b/mail_editor/views.py
new file mode 100644
index 0000000..825b712
--- /dev/null
+++ b/mail_editor/views.py
@@ -0,0 +1,10 @@
+from django.http import HttpResponse
+from django.views.generic import View
+
+from .utils import variable_help_text
+
+
+class TemplateVariableView(View):
+    def get(self, request, *args, **kwargs):
+        variables = variable_help_text(kwargs.get('template_type'))
+        return HttpResponse(variables)
diff --git a/tests/settings.py b/tests/settings.py
index 681b49a..f0b799f 100644
--- a/tests/settings.py
+++ b/tests/settings.py
@@ -30,3 +30,16 @@
         'OPTIONS': {},
     },
 ]
+
+MAIL_EDITOR_TEMPLATES = {
+    'template': {
+        'subject': [{
+            'name': 'foo',
+            'required': True,
+        }],
+        'body': [{
+            'name': 'bar',
+            'required': True,
+        }],
+    }
+}
diff --git a/tests/test_template_validation.py b/tests/test_template_validation.py
index c15f90e..75b5091 100644
--- a/tests/test_template_validation.py
+++ b/tests/test_template_validation.py
@@ -21,6 +21,7 @@
     }
 }
 
+
 class TemplateValidationTests(TestCase):
     def test_valid_template(self):
         settings.MAIL_EDITOR_CONF = CONFIG.copy()
@@ -34,7 +35,6 @@ def test_valid_template(self):
         except ValidationError:
             pytest.fail("Unexpected validationError")
 
-
     def test_template_syntax_error(self):
         settings.MAIL_EDITOR_CONF = CONFIG.copy()
         template = MailTemplate(
@@ -45,5 +45,16 @@ def test_template_syntax_error(self):
         with pytest.raises(ValidationError) as excinfo:
             validate_template(template)
 
-        print(excinfo.value)
-        self.assertEqual(excinfo.value.error_code, 'syntax_error')
+        self.assertEqual(excinfo.value.code, 'syntax_error')
+
+    def test_template_invalid_error(self):
+        settings.MAIL_EDITOR_CONF = CONFIG.copy()
+        template = MailTemplate(
+            template_type='template',
+            subject='{{ bar }}',
+            body='{{ bar }}'
+        )
+        with pytest.raises(ValidationError) as excinfo:
+            validate_template(template)
+
+        self.assertEqual(excinfo.value.message, 'These variables are required, but missing: {{ foo }}')