diff --git a/kohi/base.py b/kohi/base.py
index 864da4b..65723c3 100644
--- a/kohi/base.py
+++ b/kohi/base.py
@@ -57,6 +57,10 @@ def __init__(
         self._label: str = ''
         self._mutations: t.List[t.Callable[[t.Any], t.Any]] = []
 
+        self._is_required = True
+        self._required_error = '{label} is a required field'
+        self._default_value = None
+
     def __repr__(self):
         return f'<{self.__class__.__name__} of kohi>'
 
@@ -89,9 +93,21 @@ def _run_validators(self, data: t.Any):
             if error:
                 self._errors.append(error)
 
-    def _validate(self, data: t.Any):
-        self._run_validators(data)
-        self._handle_errors()                
+    def _return_or_default(self, data: t.Any):
+        if not data is None:
+            return data
+
+        if self._is_required and self._default_value is None:
+            error = self._required_error.format(label=self._label)
+            self._errors.insert(0, error)
+            return
+
+        return copy.deepcopy(self._default_value)
+
+    def _validate(self, data: t.Any, checks=True):
+        if checks and (data := self._return_or_default(data)) != None:
+            self._run_validators(data)
+        self._handle_errors()
         return len(self.errors) == 0
 
     def validate(self, data: t.Any):
@@ -101,11 +117,13 @@ def validate(self, data: t.Any):
 
     def parse(self, data: t.Any):
         """Analyzes the data and returns after passing the validation step"""
-        cloned = copy.deepcopy(data)
+        cloned = copy.deepcopy(self._return_or_default(data))
+
+        if (cloned != data and data == None) or (cloned == data == None and not self._is_required):
+            return cloned
 
         try:
-            if not self.validate(cloned):
-                self._handle_errors()
+            self.throw()._validate(cloned, False)
         except Exception as e:
             raise ParseError(str(e)) from e
 
@@ -130,4 +148,17 @@ def throw(self):
     def label(self, text: str):
         self._label = text
         return self
+
+    def default(self, data: t.Any):
+        self._default_value = data
+        return self
+
+    def optional(self):
+        self._is_required = False    
+        return self
+
+    def required(self, message: str='{label} is a required field'):
+        self._is_required = True
+        self._required_error = message
+        return self
         
\ No newline at end of file
diff --git a/kohi/dictionary.py b/kohi/dictionary.py
index f29f9f1..62c92fc 100644
--- a/kohi/dictionary.py
+++ b/kohi/dictionary.py
@@ -38,13 +38,6 @@ def validator(data, parent):
 
             self.add_validator(f'valide-{key}', validator)
 
-    def validate(self, data: t.Any):
-        """Validate the given data against the schema"""
-        self.reset()
+    def _validate(self, data: t.Any, checks=True):
         self._validate_props()
-        for validator in self._validators:
-            error = validator(data, self) # type: ignore
-            if error:
-                self._errors.append(error)
-        self._handle_errors()                
-        return len(self.errors) == 0
\ No newline at end of file
+        return super()._validate(data, checks)
\ No newline at end of file
diff --git a/tests/test_base.py b/tests/test_base.py
index bad8586..cda18c9 100644
--- a/tests/test_base.py
+++ b/tests/test_base.py
@@ -1,17 +1,14 @@
 from kohi.base import BaseSchema
 from kohi.exceptions import ValidationError, ParseError
 
-def assert_supress_error(fn, error=ValidationError, negate=False):
-    def wrap(*args, **kwargs):
-        try:
-            if negate:
-                assert not fn(*args, **kwargs)
-            else:
-                assert fn(*args, **kwargs)
-        except Exception as e:
-            assert isinstance(e, error)
-            
-    return wrap
+def assert_raise(fn, error=ValidationError, negate=False):
+    try:
+        if negate:
+            assert not fn()
+        else:
+            assert fn()
+    except Exception as e:
+        assert isinstance(e, error)
 
 def test_add_validator():
     b = BaseSchema(list)
@@ -48,11 +45,8 @@ def test_custom_messages():
     assert ob1.errors[0] == message.format(label='object_test', types='tuple')
 
 def test_raise():
-    se = assert_supress_error(BaseSchema(tuple).throw().validate)
-    se(True)
-    
-    se = assert_supress_error(BaseSchema(str).throw().validate)
-    se(10)
+    assert_raise(lambda: BaseSchema(tuple).throw().validate(True))
+    assert_raise(lambda: BaseSchema(str).throw().validate(10))
 
 def test_parse():
     b = BaseSchema(str)
@@ -65,3 +59,10 @@ def test_mutations():
     b.add_mutation(lambda a: a.replace('l', 'K'))
 
     assert b.parse('loki') == 'Kohi'
+
+def test_required():
+    b = BaseSchema(int).label('test')
+    
+    assert not b.validate(None)
+    assert b.optional().parse(None) == None
+    assert_raise(lambda: b.required().parse(None), ParseError)
diff --git a/tests/test_dictionary.py b/tests/test_dictionary.py
index eee52f8..e6e919a 100644
--- a/tests/test_dictionary.py
+++ b/tests/test_dictionary.py
@@ -14,14 +14,9 @@ def test_base():
 def test_errors_list():
     d = DictSchema().props(
         name=StringSchema().length(4),
-        age=NumberSchema().lte(1)
+        age=NumberSchema().lte(1).default(1)
     )
 
     assert d.validate({ 'name': 'kohi', 'age': 1 })
     assert not d.validate({ 'name': 'Github', 'age': 15 })
-    # assert not d.validate({ 'name': 'Gitlab' })
-
-# def test_not_one_of():
-#     assert EnumSchema().not_one_of([1]).validate('1')
-#     assert not EnumSchema().not_one_of([1]).validate(1)
-#     assert not EnumSchema().not_one_of(['1']).validate('1')
\ No newline at end of file
+    assert d.throw().validate({ 'name': 'Gitlab' })