diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58ef000..150dfde 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,12 @@
 # Changelog
 
+## 0.9.0
+
++ Fix to make experimental `Waiter` usable
++ Suspend `glue()` release indefinitely
++ Add `yesno()`
++ Document validators
+
 ## 0.8.2 and 0.7.9
 
 + `.color`: fix `chalk` not behaving as expected
diff --git a/README.md b/README.md
index 5b9a797..3a08b1e 100644
--- a/README.md
+++ b/README.md
@@ -28,11 +28,11 @@ Please note that you probably already have those dependencies, if you just use t
 
 ## Features
 
-...
+Read the [documentation](https://suou.readthedocs.io/).
 
 ## Support
 
-Just a heads up: SUOU was made to support Sakuragasaki46 (me)'s own selfish, egoistic needs. Not to provide a service to the public.
+Just a heads up: SUOU was made to support Sakuragasaki46 (me)'s own selfish, egoistic needs. Not certainly to provide a service to the public.
 
 As a consequence, 'add this add that' stuff is best-effort.
 
diff --git a/docs/index.rst b/docs/index.rst
index 12e5d40..9c3d855 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -15,4 +15,5 @@ ease programmer's QoL and write shorter and cleaner code that works.
    
    sqlalchemy
    iding
+   validators
    api
\ No newline at end of file
diff --git a/docs/validators.rst b/docs/validators.rst
new file mode 100644
index 0000000..e878900
--- /dev/null
+++ b/docs/validators.rst
@@ -0,0 +1,15 @@
+
+validators
+==================
+
+.. currentmodule:: suou.validators
+
+Validators for use in frameworks such as Pydantic or Marshmallow.
+
+.. autofunction:: matches
+
+.. autofunction:: not_greater_than
+
+.. autofunction:: not_less_than
+
+.. autofunction:: yesno
\ No newline at end of file
diff --git a/src/suou/__init__.py b/src/suou/__init__.py
index a74a37a..a7c96c8 100644
--- a/src/suou/__init__.py
+++ b/src/suou/__init__.py
@@ -32,12 +32,12 @@ from .signing import UserSigner
 from .snowflake import Snowflake, SnowflakeGen
 from .lex import symbol_table, lex, ilex
 from .strtools import PrefixIdentifier
-from .validators import matches
+from .validators import matches, not_less_than, not_greater_than, yesno
 from .redact import redact_url_password
 from .http import WantsContentType
 from .color import chalk, WebColor
 
-__version__ = "0.8.2"
+__version__ = "0.9.0"
 
 __all__ = (
     'ConfigOptions', 'ConfigParserConfigSource', 'ConfigSource', 'ConfigValue',
@@ -51,9 +51,10 @@ __all__ = (
     'cb32decode', 'chalk', 'count_ones', 'dei_args', 'deprecated',
     'future', 'ilex', 'join_bits',
     'jsonencode', 'kwargs_prefix', 'lex', 'ltuple', 'makelist', 'mask_shift',
-    'matches', 'mod_ceil', 'mod_floor', 'none_pass', 'not_implemented',
+    'matches', 'mod_ceil', 'mod_floor', 'must_be', 'none_pass', 'not_implemented',
+    'not_less_than', 'not_greater_than',
     'redact_url_password', 'rtuple', 'split_bits', 'ssv_list', 'symbol_table',
     'timed_cache', 'twocolon_list', 'want_bytes', 'want_datetime', 'want_isodate',
-    'want_str', 'want_timestamp', 'want_urlsafe', 'want_urlsafe_bytes',
+    'want_str', 'want_timestamp', 'want_urlsafe', 'want_urlsafe_bytes', 'yesno',
     'z85encode', 'z85decode'
 )
diff --git a/src/suou/calendar.py b/src/suou/calendar.py
index d2af051..f738b88 100644
--- a/src/suou/calendar.py
+++ b/src/suou/calendar.py
@@ -17,7 +17,6 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 
 import datetime
 
-from suou.functools import not_implemented
 from suou.luck import lucky
 from suou.validators import not_greater_than
 
diff --git a/src/suou/glue.py b/src/suou/glue.py
index 3f1a799..6368deb 100644
--- a/src/suou/glue.py
+++ b/src/suou/glue.py
@@ -22,7 +22,7 @@ from suou.classtools import MISSING
 from suou.functools import future
 
 
-@future(version="0.9.0")
+@future()
 class FakeModule(ModuleType):
     """
     Fake module used in @glue() in case of import error
@@ -34,12 +34,12 @@ class FakeModule(ModuleType):
         raise AttributeError(f'Module {self.__name__} not found; this feature is not available ({self._exc})') from self._exc
 
 
-@future(version = "0.9.0")
+@future()
 def glue(*modules):
     """
     Helper for "glue" code -- it imports the given modules and passes them as keyword arguments to the wrapped functions.
 
-    NEW 0.9.0
+    EXPERIMENTAL
     """
     module_dict = dict()
     imports_succeeded = True
diff --git a/src/suou/validators.py b/src/suou/validators.py
index 53a7be3..e8b366f 100644
--- a/src/suou/validators.py
+++ b/src/suou/validators.py
@@ -18,6 +18,10 @@ import re
 
 from typing import Any, Iterable, TypeVar
 
+from suou.classtools import MISSING
+
+from .functools import future
+
 _T = TypeVar('_T')
 
 def matches(regex: str | int, /, length: int = 0, *, flags=0):
@@ -55,5 +59,13 @@ def not_less_than(y):
     """
     return lambda x: x >= y
 
-__all__ = ('matches', 'not_greater_than')
+def yesno(x: str) -> bool:
+    """
+    Returns False if x.lower() is in '0', '', 'no', 'n', 'false' or 'off'.
+
+    *New in 0.9.0*
+    """
+    return x not in (None, MISSING) and x.lower() not in ('', '0', 'off', 'n', 'no', 'false', 'f')
+
+__all__ = ('matches', 'must_be', 'not_greater_than', 'not_less_than', 'yesno')
 
diff --git a/src/suou/waiter.py b/src/suou/waiter.py
index 51e4590..a959c88 100644
--- a/src/suou/waiter.py
+++ b/src/suou/waiter.py
@@ -17,6 +17,7 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 """
 
 
+from typing import Callable
 import warnings
 from starlette.applications import Starlette
 from starlette.responses import JSONResponse, PlainTextResponse, Response
@@ -27,15 +28,22 @@ from suou.functools import future
 
 @future()
 class Waiter():
+    _cached_app: Callable | None = None
+
     def __init__(self):
         self.routes: list[Route] = []
         self.production = False
-
+        
+    async def __call__(self, *args):
+        return await self._build_app()(*args)
+    
     def _build_app(self) -> Starlette:
-        return Starlette(
-            debug = not self.production,
-            routes= self.routes
-        )
+        if not self._cached_app:
+            self._cached_app = Starlette(
+                debug = not self.production,
+                routes= self.routes
+            )
+        return self._cached_app 
 
     def get(self, endpoint: str, *a, **k):
         return self._route('GET', endpoint, *a, **k)
diff --git a/tests/test_validators.py b/tests/test_validators.py
new file mode 100644
index 0000000..0064128
--- /dev/null
+++ b/tests/test_validators.py
@@ -0,0 +1,24 @@
+
+
+import unittest
+from suou.validators import yesno
+
+class TestValidators(unittest.TestCase):
+    def setUp(self):
+        ...
+    def tearDown(self):
+        ...
+    def test_yesno(self):
+        self.assertFalse(yesno('false'))
+        self.assertFalse(yesno('FALSe'))
+        self.assertTrue(yesno('fasle'))
+        self.assertTrue(yesno('falso'))
+        self.assertTrue(yesno('zero'))
+        self.assertTrue(yesno('true'))
+        self.assertFalse(yesno('0'))
+        self.assertTrue(yesno('00'))
+        self.assertTrue(yesno('.'))
+        self.assertTrue(yesno('2'))
+        self.assertTrue(yesno('o'))
+        self.assertFalse(yesno('oFF'))
+        self.assertFalse(yesno('no'))
\ No newline at end of file