diff --git a/.gitignore b/.gitignore
index 150127b5..9a31971a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -73,3 +73,8 @@ venv
 # Other
 .directory
 
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index ae3914e2..a9a07809 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,6 +1,13 @@
 Changelog
 ---------
 
+2.20.5 (unreleased)
++++++++++++++++++++
+
+Bug fixes:
+
+- Fix behavior when a non-list collection is passed to the ``validate`` argument of ``fields.Email`` and ``fields.URL`` (:issue:`1400`).
+
 2.20.4 (2019-09-11)
 +++++++++++++++++++
 
diff --git a/src/marshmallow/fields.py b/src/marshmallow/fields.py
index 5187f91c..bf2e9f8a 100755
--- a/src/marshmallow/fields.py
+++ b/src/marshmallow/fields.py
@@ -1128,13 +1128,14 @@ class Url(ValidatedField, String):
         String.__init__(self, **kwargs)
 
         self.relative = relative
-        # Insert validation into self.validators so that multiple errors can be
-        # stored.
-        self.validators.insert(0, validate.URL(
-            relative=self.relative,
-            schemes=schemes,
-            error=self.error_messages['invalid']
-        ))
+        # Insert validation into self.validators so that multiple errors can be stored.
+        self.validators = (
+            [validate.URL(
+                relative=self.relative,
+                schemes=schemes,
+                error=self.error_messages['invalid']
+            )] + list(self.validators)
+        )
 
     def _validated(self, value):
         if value is None:
@@ -1156,9 +1157,10 @@ class Email(ValidatedField, String):
 
     def __init__(self, *args, **kwargs):
         String.__init__(self, *args, **kwargs)
-        # Insert validation into self.validators so that multiple errors can be
-        # stored.
-        self.validators.insert(0, validate.Email(error=self.error_messages['invalid']))
+        # Insert validation into self.validators so that multiple errors can be stored.
+        self.validators = (
+            [validate.Email(error=self.error_messages['invalid'])] + list(self.validators)
+        )
 
     def _validated(self, value):
         if value is None:

Uncaught error when passing non-list validators to Email and URL fields
`fields.Email` and `fields.URL` error if a non-list is passed to `validate`.

```python
from marshmallow import Schema, fields, validate

class UserSchema(Schema):
    email = fields.Email(validate=(validate.Length(min=5), ))
    url = fields.URL(validate=(validate.Length(min=5), ))
```

```
AttributeError: 'tuple' object has no attribute 'insert'
```
diff --git a/tests/test_deserialization.py b/tests/test_deserialization.py
index bd7afc27..dd0aa280 100644
--- a/tests/test_deserialization.py
+++ b/tests/test_deserialization.py
@@ -475,6 +475,12 @@ class TestFieldDeserialization:
             field.deserialize('/foo/bar')
         assert excinfo.value.args[0][0] == 'Not a valid URL.'
 
+    # regression test for https://github.com/marshmallow-code/marshmallow/issues/1400
+    def test_url_field_non_list_validators(self):
+        field = fields.Url(validate=(validate.Length(min=16), ))
+        with pytest.raises(ValidationError, match="Shorter than minimum length"):
+            field.deserialize('https://abc.def')
+
     def test_relative_url_field_deserialization(self):
         field = fields.Url(relative=True)
         assert field.deserialize('/foo/bar') == '/foo/bar'
@@ -494,6 +500,12 @@ class TestFieldDeserialization:
             field.deserialize('invalidemail')
         assert excinfo.value.args[0][0] == 'Not a valid email address.'
 
+    # regression test for https://github.com/marshmallow-code/marshmallow/issues/1400
+    def test_email_field_non_list_validators(self):
+        field = fields.Email(validate=(validate.Length(min=9), ))
+        with pytest.raises(ValidationError, match="Shorter than minimum length"):
+            field.deserialize('a@bc.com')
+
     def test_function_field_deserialization_is_noop_by_default(self):
         field = fields.Function(lambda x: None)
         # Default is noop

pip install -e .[dev]
parse_log_pytest
requirements.txt
pytest
apt-get update apt-get install -y gcc
3.7
requirements/base.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
cachetools==5.5.2
certifi @ file:///croot/certifi_1671487769961/work/certifi
chardet==5.2.0
colorama==0.4.6
distlib==0.3.9
entrypoints==0.3
exceptiongroup==1.2.2
filelock==3.12.2
flake8==3.7.4
importlib-metadata==6.7.0
iniconfig==2.0.0
-e git+https://github.com/marshmallow-code/marshmallow.git@8e217c8d6fefb7049ab3389f31a8d35824fa2d96#egg=marshmallow
mccabe==0.6.1
packaging==24.0
platformdirs==4.0.0
pluggy==1.2.0
pycodestyle==2.5.0
pyflakes==2.1.1
pyproject-api==1.5.3
pytest==7.4.4
python-dateutil==2.9.0.post0
pytz==2025.2
simplejson==3.20.1
six==1.17.0
tomli==2.0.1
tox==4.8.0
typing_extensions==4.7.1
virtualenv==20.26.6
zipp==3.15.0

name: marshmallow
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2022.12.7=py37h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - pip=22.3.1=py37h06a4308_0
  - python=3.7.16=h7a1cb2a_0
  - readline=8.2=h5eee18b_0
  - setuptools=65.6.3=py37h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - wheel=0.38.4=py37h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - cachetools==5.5.2
      - chardet==5.2.0
      - colorama==0.4.6
      - distlib==0.3.9
      - entrypoints==0.3
      - exceptiongroup==1.2.2
      - filelock==3.12.2
      - flake8==3.7.4
      - importlib-metadata==6.7.0
      - iniconfig==2.0.0
      - mccabe==0.6.1
      - packaging==24.0
      - platformdirs==4.0.0
      - pluggy==1.2.0
      - pycodestyle==2.5.0
      - pyflakes==2.1.1
      - pyproject-api==1.5.3
      - pytest==7.4.4
      - python-dateutil==2.9.0.post0
      - pytz==2025.2
      - simplejson==3.20.1
      - six==1.17.0
      - tomli==2.0.1
      - tox==4.8.0
      - typing-extensions==4.7.1
      - virtualenv==20.26.6
      - zipp==3.15.0
prefix: /opt/conda/envs/marshmallow

tests/test_deserialization.py::TestFieldDeserialization::test_url_field_non_list_validators tests/test_deserialization.py::TestFieldDeserialization::test_email_field_non_list_validators
tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[String] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[Integer] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[Boolean] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[Float] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[Number] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[DateTime] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[LocalDateTime] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[Time] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[Date] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[TimeDelta] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[Dict] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[Url] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[Email] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[FormattedString] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[UUID] tests/test_deserialization.py::TestDeserializingNone::test_fields_allow_none_deserialize_to_none[Decimal] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[String] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[Integer] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[Boolean] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[Float] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[Number] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[DateTime] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[LocalDateTime] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[Time] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[Date] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[TimeDelta] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[Dict] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[Url] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[Email] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[FormattedString] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[UUID] tests/test_deserialization.py::TestDeserializingNone::test_fields_dont_allow_none_by_default[Decimal] tests/test_deserialization.py::TestDeserializingNone::test_allow_none_is_true_if_missing_is_true tests/test_deserialization.py::TestDeserializingNone::test_list_field_deserialize_none_to_empty_list tests/test_deserialization.py::TestFieldDeserialization::test_float_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_invalid_float_field_deserialization[bad] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_float_field_deserialization[] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_float_field_deserialization[in_val2] tests/test_deserialization.py::TestFieldDeserialization::test_float_field_overflow tests/test_deserialization.py::TestFieldDeserialization::test_integer_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_decimal_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_decimal_field_with_places tests/test_deserialization.py::TestFieldDeserialization::test_decimal_field_with_places_and_rounding tests/test_deserialization.py::TestFieldDeserialization::test_decimal_field_deserialization_string tests/test_deserialization.py::TestFieldDeserialization::test_decimal_field_special_values tests/test_deserialization.py::TestFieldDeserialization::test_decimal_field_special_values_not_permitted tests/test_deserialization.py::TestFieldDeserialization::test_string_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_boolean_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_boolean_field_deserialization_with_custom_truthy_values tests/test_deserialization.py::TestFieldDeserialization::test_boolean_field_deserialization_with_custom_truthy_values_invalid[notvalid] tests/test_deserialization.py::TestFieldDeserialization::test_boolean_field_deserialization_with_custom_truthy_values_invalid[123] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_datetime_deserialization[not-a-datetime] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_datetime_deserialization[42] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_datetime_deserialization[] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_datetime_deserialization[in_value3] tests/test_deserialization.py::TestFieldDeserialization::test_datetime_passed_year_is_invalid tests/test_deserialization.py::TestFieldDeserialization::test_custom_date_format_datetime_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_rfc_datetime_field_deserialization[rfc] tests/test_deserialization.py::TestFieldDeserialization::test_rfc_datetime_field_deserialization[rfc822] tests/test_deserialization.py::TestFieldDeserialization::test_iso_datetime_field_deserialization[iso] tests/test_deserialization.py::TestFieldDeserialization::test_iso_datetime_field_deserialization[iso8601] tests/test_deserialization.py::TestFieldDeserialization::test_localdatetime_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_time_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_invalid_time_field_deserialization[badvalue] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_time_field_deserialization[] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_time_field_deserialization[in_data2] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_time_field_deserialization[42] tests/test_deserialization.py::TestFieldDeserialization::test_timedelta_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_invalid_timedelta_field_deserialization[] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_timedelta_field_deserialization[badvalue] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_timedelta_field_deserialization[in_value2] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_timedelta_field_deserialization[9999999999] tests/test_deserialization.py::TestFieldDeserialization::test_date_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_invalid_date_field_deserialization[] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_date_field_deserialization[123] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_date_field_deserialization[in_value2] tests/test_deserialization.py::TestFieldDeserialization::test_dict_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_url_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_relative_url_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_url_field_schemes_argument tests/test_deserialization.py::TestFieldDeserialization::test_email_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_function_field_deserialization_is_noop_by_default tests/test_deserialization.py::TestFieldDeserialization::test_function_field_deserialization_with_callable tests/test_deserialization.py::TestFieldDeserialization::test_function_field_deserialization_with_context tests/test_deserialization.py::TestFieldDeserialization::test_uuid_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_invalid_uuid_deserialization[malformed] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_uuid_deserialization[123] tests/test_deserialization.py::TestFieldDeserialization::test_invalid_uuid_deserialization[in_value2] tests/test_deserialization.py::TestFieldDeserialization::test_deserialization_function_must_be_callable tests/test_deserialization.py::TestFieldDeserialization::test_method_field_deserialization_is_noop_by_default tests/test_deserialization.py::TestFieldDeserialization::test_deserialization_method tests/test_deserialization.py::TestFieldDeserialization::test_deserialization_method_must_be_a_method tests/test_deserialization.py::TestFieldDeserialization::test_method_field_deserialize_only tests/test_deserialization.py::TestFieldDeserialization::test_datetime_list_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_list_field_deserialize_invalid_item tests/test_deserialization.py::TestFieldDeserialization::test_list_field_deserialize_multiple_invalid_items tests/test_deserialization.py::TestFieldDeserialization::test_list_field_deserialize_value_that_is_not_a_list[notalist] tests/test_deserialization.py::TestFieldDeserialization::test_list_field_deserialize_value_that_is_not_a_list[42] tests/test_deserialization.py::TestFieldDeserialization::test_list_field_deserialize_value_that_is_not_a_list[value2] tests/test_deserialization.py::TestFieldDeserialization::test_constant_field_deserialization tests/test_deserialization.py::TestFieldDeserialization::test_constant_is_always_included_in_deserialized_data tests/test_deserialization.py::TestFieldDeserialization::test_field_deserialization_with_user_validator_function tests/test_deserialization.py::TestFieldDeserialization::test_field_deserialization_with_user_validator_class_that_returns_bool tests/test_deserialization.py::TestFieldDeserialization::test_field_deserialization_with_user_validator_that_raises_error_with_list tests/test_deserialization.py::TestFieldDeserialization::test_validator_must_return_false_to_raise_error tests/test_deserialization.py::TestFieldDeserialization::test_field_deserialization_with_validator_with_nonascii_input tests/test_deserialization.py::TestFieldDeserialization::test_field_deserialization_with_user_validators tests/test_deserialization.py::TestFieldDeserialization::test_field_deserialization_with_custom_error_message tests/test_deserialization.py::TestFieldDeserialization::test_field_deserialization_with_non_utf8_value tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_to_dict tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_with_missing_values tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_many tests/test_deserialization.py::TestSchemaDeserialization::test_exclude tests/test_deserialization.py::TestSchemaDeserialization::test_nested_single_deserialization_to_dict tests/test_deserialization.py::TestSchemaDeserialization::test_nested_list_deserialization_to_dict tests/test_deserialization.py::TestSchemaDeserialization::test_nested_single_none_not_allowed tests/test_deserialization.py::TestSchemaDeserialization::test_nested_many_non_not_allowed tests/test_deserialization.py::TestSchemaDeserialization::test_nested_single_required_missing tests/test_deserialization.py::TestSchemaDeserialization::test_nested_many_required_missing tests/test_deserialization.py::TestSchemaDeserialization::test_none_deserialization tests/test_deserialization.py::TestSchemaDeserialization::test_nested_none_deserialization tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_with_attribute_param tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_with_attribute_param_symmetry tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_with_attribute_param_error_returns_field_name_not_attribute_name tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_with_attribute_param_error_returns_load_from_not_attribute_name tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_with_load_from_param tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_with_dump_only_param tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_with_missing_param_value tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_with_missing_param_callable tests/test_deserialization.py::TestSchemaDeserialization::test_deserialize_with_missing_param_none tests/test_deserialization.py::TestSchemaDeserialization::test_deserialization_returns_errors tests/test_deserialization.py::TestSchemaDeserialization::test_deserialization_returns_errors_with_multiple_validators tests/test_deserialization.py::TestSchemaDeserialization::test_strict_mode_deserialization tests/test_deserialization.py::TestSchemaDeserialization::test_strict_mode_many tests/test_deserialization.py::TestSchemaDeserialization::test_strict_mode_deserialization_with_multiple_validators tests/test_deserialization.py::TestSchemaDeserialization::test_uncaught_validation_errors_are_stored tests/test_deserialization.py::TestSchemaDeserialization::test_multiple_errors_can_be_stored_for_a_field tests/test_deserialization.py::TestSchemaDeserialization::test_multiple_errors_can_be_stored_for_an_email_field tests/test_deserialization.py::TestSchemaDeserialization::test_multiple_errors_can_be_stored_for_a_url_field tests/test_deserialization.py::TestSchemaDeserialization::test_required_value_only_passed_to_validators_if_provided tests/test_deserialization.py::TestSchemaDeserialization::test_partial_deserialization[True] tests/test_deserialization.py::TestSchemaDeserialization::test_partial_deserialization[False] tests/test_deserialization.py::TestSchemaDeserialization::test_partial_fields_deserialization tests/test_deserialization.py::TestSchemaDeserialization::test_partial_fields_validation tests/test_deserialization.py::TestValidation::test_integer_with_validator tests/test_deserialization.py::TestValidation::test_integer_with_validators[field0] tests/test_deserialization.py::TestValidation::test_integer_with_validators[field1] tests/test_deserialization.py::TestValidation::test_integer_with_validators[field2] tests/test_deserialization.py::TestValidation::test_float_with_validators[field0] tests/test_deserialization.py::TestValidation::test_float_with_validators[field1] tests/test_deserialization.py::TestValidation::test_float_with_validators[field2] tests/test_deserialization.py::TestValidation::test_string_validator tests/test_deserialization.py::TestValidation::test_function_validator tests/test_deserialization.py::TestValidation::test_function_validators[field0] tests/test_deserialization.py::TestValidation::test_function_validators[field1] tests/test_deserialization.py::TestValidation::test_function_validators[field2] tests/test_deserialization.py::TestValidation::test_method_validator tests/test_deserialization.py::TestValidation::test_nested_data_is_stored_when_validation_fails tests/test_deserialization.py::TestValidation::test_false_value_validation tests/test_deserialization.py::test_required_field_failure[String] tests/test_deserialization.py::test_required_field_failure[Integer] tests/test_deserialization.py::test_required_field_failure[Boolean] tests/test_deserialization.py::test_required_field_failure[Float] tests/test_deserialization.py::test_required_field_failure[Number] tests/test_deserialization.py::test_required_field_failure[DateTime] tests/test_deserialization.py::test_required_field_failure[LocalDateTime] tests/test_deserialization.py::test_required_field_failure[Time] tests/test_deserialization.py::test_required_field_failure[Date] tests/test_deserialization.py::test_required_field_failure[TimeDelta] tests/test_deserialization.py::test_required_field_failure[Dict] tests/test_deserialization.py::test_required_field_failure[Url] tests/test_deserialization.py::test_required_field_failure[Email] tests/test_deserialization.py::test_required_field_failure[UUID] tests/test_deserialization.py::test_required_field_failure[Decimal] tests/test_deserialization.py::test_required_message_can_be_changed[My tests/test_deserialization.py::test_required_message_can_be_changed[message1] tests/test_deserialization.py::test_required_message_can_be_changed[message2] tests/test_deserialization.py::test_deserialize_doesnt_raise_exception_if_strict_is_false_and_input_type_is_incorrect tests/test_deserialization.py::test_deserialize_raises_exception_if_strict_is_true_and_input_type_is_incorrect
.gitignore src/marshmallow/fields.py CHANGELOG.rst
.gitignore src/marshmallow/fields.py CHANGELOG.rst