diff --git a/ci/check_sdist.py b/ci/check_sdist.py
index 5fd008f3..b3ff18de 100755
--- a/ci/check_sdist.py
+++ b/ci/check_sdist.py
@@ -3,7 +3,6 @@
 
 import sys
 import tarfile
-from tarfile import TarFile
 
 expected_files = [
     "docs/requirements.txt",
diff --git a/docs/generate-metrics.py b/docs/generate-metrics.py
index 81304bef..05cc6c35 100644
--- a/docs/generate-metrics.py
+++ b/docs/generate-metrics.py
@@ -1,5 +1,4 @@
 import os
-from os.path import join
 
 from pytablewriter import RstSimpleTableWriter
 from pytablewriter.style import Style
diff --git a/jupyterhub/alembic/versions/19c0846f6344_base_revision_for_0_5.py b/jupyterhub/alembic/versions/19c0846f6344_base_revision_for_0_5.py
index 7734993a..c8421da4 100644
--- a/jupyterhub/alembic/versions/19c0846f6344_base_revision_for_0_5.py
+++ b/jupyterhub/alembic/versions/19c0846f6344_base_revision_for_0_5.py
@@ -11,8 +11,6 @@ down_revision = None
 branch_labels = None
 depends_on = None
 
-import sqlalchemy as sa
-from alembic import op
 
 def upgrade():
     pass
diff --git a/jupyterhub/apihandlers/hub.py b/jupyterhub/apihandlers/hub.py
index 47a4a6e5..4474c821 100644
--- a/jupyterhub/apihandlers/hub.py
+++ b/jupyterhub/apihandlers/hub.py
@@ -5,7 +5,6 @@ import json
 import sys
 
 from tornado import web
-from tornado.ioloop import IOLoop
 
 from .._version import __version__
 from ..scopes import needs_scope
diff --git a/jupyterhub/auth.py b/jupyterhub/auth.py
index e31cd395..2795a781 100644
--- a/jupyterhub/auth.py
+++ b/jupyterhub/auth.py
@@ -776,8 +776,6 @@ def _deprecated_method(old_name, new_name, version):
     return deprecated
 
 
-import types
-
 # deprecate white/blacklist method names
 for _old_name, _new_name, _version in [
     ("check_whitelist", "check_allowed", "1.2"),
diff --git a/jupyterhub/oauth/provider.py b/jupyterhub/oauth/provider.py
index d3e17c46..bb72e338 100644
--- a/jupyterhub/oauth/provider.py
+++ b/jupyterhub/oauth/provider.py
@@ -13,7 +13,6 @@ from ..scopes import (
     _check_scopes_exist,
     _resolve_requested_scopes,
     access_scopes,
-    expand_scopes,
     identify_scopes,
 )
 from ..utils import compare_token, hash_token
diff --git a/jupyterhub/orm.py b/jupyterhub/orm.py
index ea8f54d8..0aa1e1ca 100644
--- a/jupyterhub/orm.py
+++ b/jupyterhub/orm.py
@@ -35,7 +35,6 @@ from sqlalchemy.orm import (
     sessionmaker,
 )
 from sqlalchemy.pool import StaticPool
-from sqlalchemy.sql.expression import bindparam
 from sqlalchemy.types import LargeBinary, Text, TypeDecorator
 from tornado.log import app_log
 
@@ -996,7 +995,6 @@ def check_db_revision(engine):
     ).first()[0]
     if alembic_revision == head:
         app_log.debug("database schema version found: %s", alembic_revision)
-        pass
     else:
         raise DatabaseSchemaMismatch(
             "Found database schema version {found} != {head}. "
diff --git a/jupyterhub/proxy.py b/jupyterhub/proxy.py
index dbe0fcdb..87b47a6c 100644
--- a/jupyterhub/proxy.py
+++ b/jupyterhub/proxy.py
@@ -250,14 +250,12 @@ class Proxy(LoggingConfigurable):
         The proxy implementation should also have a way to associate the fact that a
         route came from JupyterHub.
         """
-        pass
 
     async def delete_route(self, routespec):
         """Delete a route with a given routespec if it exists.
 
         **Subclasses must define this method**
         """
-        pass
 
     async def get_all_routes(self):
         """Fetch and return all the routes associated by JupyterHub from the
@@ -274,7 +272,6 @@ class Proxy(LoggingConfigurable):
             'data': the attached data dict for this route (as specified in add_route)
           }
         """
-        pass
 
     async def get_route(self, routespec):
         """Return the route info for a given routespec.
@@ -683,7 +680,6 @@ class ConfigurableHTTPProxy(Proxy):
             os.remove(self.pid_file)
         except FileNotFoundError:
             self.log.debug("PID file %s already removed", self.pid_file)
-            pass
 
     def _get_ssl_options(self):
         """List of cmd proxy options to use internal SSL"""
diff --git a/jupyterhub/services/auth.py b/jupyterhub/services/auth.py
index d61239e5..24106ee2 100644
--- a/jupyterhub/services/auth.py
+++ b/jupyterhub/services/auth.py
@@ -35,7 +35,6 @@ import string
 import time
 import uuid
 import warnings
-from functools import partial
 from http import HTTPStatus
 from unittest import mock
 from urllib.parse import urlencode
diff --git a/jupyterhub/singleuser/mixins.py b/jupyterhub/singleuser/mixins.py
index 953d3d27..dfad82ca 100755
--- a/jupyterhub/singleuser/mixins.py
+++ b/jupyterhub/singleuser/mixins.py
@@ -14,7 +14,6 @@ import logging
 import os
 import random
 import secrets
-import ssl
 import sys
 import warnings
 from datetime import timezone
diff --git a/jupyterhub/spawner.py b/jupyterhub/spawner.py
index 39837b08..756fefa7 100644
--- a/jupyterhub/spawner.py
+++ b/jupyterhub/spawner.py
@@ -896,7 +896,6 @@ class Spawner(LoggingConfigurable):
         Override in subclasses to restore any extra state that is needed to track
         the single-user server for that user. Subclasses should call super().
         """
-        pass
 
     def get_state(self):
         """Save state of spawner into database.
@@ -1341,7 +1340,6 @@ class Spawner(LoggingConfigurable):
 
         Stopping a server does *not* call this method.
         """
-        pass
 
     def add_poll_callback(self, callback, *args, **kwargs):
         """Add a callback to fire when the single-user server stops"""
diff --git a/jupyterhub/tests/conftest.py b/jupyterhub/tests/conftest.py
index b200bb44..b880017b 100644
--- a/jupyterhub/tests/conftest.py
+++ b/jupyterhub/tests/conftest.py
@@ -27,7 +27,6 @@ Fixtures to add functionality or spawning behavior
 # Distributed under the terms of the Modified BSD License.
 import asyncio
 import copy
-import inspect
 import os
 import sys
 from functools import partial
@@ -36,7 +35,6 @@ from subprocess import TimeoutExpired
 from unittest import mock
 
 from pytest import fixture, raises
-from tornado import ioloop
 from tornado.httpclient import HTTPError
 from tornado.platform.asyncio import AsyncIOMainLoop
 
diff --git a/jupyterhub/tests/mocking.py b/jupyterhub/tests/mocking.py
index 561f672c..8aed2bfb 100644
--- a/jupyterhub/tests/mocking.py
+++ b/jupyterhub/tests/mocking.py
@@ -36,7 +36,6 @@ from unittest import mock
 from urllib.parse import urlparse
 
 from pamela import PAMError
-from tornado.ioloop import IOLoop
 from traitlets import Bool, Dict, default
 
 from .. import metrics, orm, roles
diff --git a/jupyterhub/tests/populate_db.py b/jupyterhub/tests/populate_db.py
index c85e8c57..33b5247b 100644
--- a/jupyterhub/tests/populate_db.py
+++ b/jupyterhub/tests/populate_db.py
@@ -4,7 +4,6 @@ Run with old versions of jupyterhub to test upgrade/downgrade
 
 used in test_db.py
 """
-import os
 from datetime import datetime
 from functools import partial
 
diff --git a/jupyterhub/tests/selenium/conftest.py b/jupyterhub/tests/selenium/conftest.py
index 06de2029..a68ce6e3 100644
--- a/jupyterhub/tests/selenium/conftest.py
+++ b/jupyterhub/tests/selenium/conftest.py
@@ -1,6 +1,5 @@
 import pytest
 from selenium import webdriver
-from selenium.webdriver.firefox.options import Options as FirefoxOptions
 
 
 @pytest.fixture()
diff --git a/jupyterhub/tests/selenium/test_browser.py b/jupyterhub/tests/selenium/test_browser.py
index 4e7ba00c..9c52878c 100644
--- a/jupyterhub/tests/selenium/test_browser.py
+++ b/jupyterhub/tests/selenium/test_browser.py
@@ -1,21 +1,14 @@
 import asyncio
-import time
 from functools import partial
 
 import pytest
-from selenium import webdriver
-from selenium.common.exceptions import NoSuchElementException, TimeoutException
-from selenium.webdriver.common.by import By
+from selenium.common.exceptions import NoSuchElementException
 from selenium.webdriver.support import expected_conditions as EC
 from selenium.webdriver.support.ui import WebDriverWait
 from tornado.escape import url_escape
 from tornado.httputil import url_concat
 
-from jupyterhub.tests.selenium.locators import (
-    HomePageLocators,
-    LoginPageLocators,
-    TokenPageLocators,
-)
+from jupyterhub.tests.selenium.locators import LoginPageLocators
 from jupyterhub.utils import exponential_backoff
 
 from ...utils import url_path_join
diff --git a/jupyterhub/tests/test_auth_expiry.py b/jupyterhub/tests/test_auth_expiry.py
index 5b750e79..876f85b8 100644
--- a/jupyterhub/tests/test_auth_expiry.py
+++ b/jupyterhub/tests/test_auth_expiry.py
@@ -7,7 +7,6 @@ authentication can expire in a number of ways:
 - doesn't need refresh
 - needs refresh and cannot be refreshed without new login
 """
-from contextlib import contextmanager
 from unittest import mock
 from urllib.parse import parse_qs, urlparse
 
diff --git a/jupyterhub/tests/test_eventlog.py b/jupyterhub/tests/test_eventlog.py
index d8dcd285..5b6649cd 100644
--- a/jupyterhub/tests/test_eventlog.py
+++ b/jupyterhub/tests/test_eventlog.py
@@ -14,8 +14,6 @@ import jsonschema
 import pytest
 from traitlets.config import Config
 
-from .mocking import MockHub
-
 # To test new schemas, add them to the `valid_events`
 # and `invalid_events` dictionary below.
 
diff --git a/jupyterhub/tests/test_orm.py b/jupyterhub/tests/test_orm.py
index 7a7f0310..3009a11d 100644
--- a/jupyterhub/tests/test_orm.py
+++ b/jupyterhub/tests/test_orm.py
@@ -7,7 +7,6 @@ from datetime import datetime, timedelta
 from unittest import mock
 
 import pytest
-from tornado import gen
 
 from .. import crypto, objects, orm, roles
 from ..emptyclass import EmptyClass
diff --git a/jupyterhub/tests/test_services.py b/jupyterhub/tests/test_services.py
index a5d50571..b1e9fe9f 100644
--- a/jupyterhub/tests/test_services.py
+++ b/jupyterhub/tests/test_services.py
@@ -6,8 +6,6 @@ from subprocess import Popen
 
 from async_generator import asynccontextmanager
 
-from .. import orm
-from ..roles import roles_to_scopes
 from ..utils import (
     exponential_backoff,
     maybe_future,
diff --git a/jupyterhub/tests/test_singleuser.py b/jupyterhub/tests/test_singleuser.py
index c45ade95..e139b41f 100644
--- a/jupyterhub/tests/test_singleuser.py
+++ b/jupyterhub/tests/test_singleuser.py
@@ -1,7 +1,7 @@
 """Tests for jupyterhub.singleuser"""
 import os
 import sys
-from contextlib import contextmanager, nullcontext
+from contextlib import nullcontext
 from subprocess import CalledProcessError, check_output
 from unittest import mock
 from urllib.parse import urlencode, urlparse
diff --git a/jupyterhub/utils.py b/jupyterhub/utils.py
index 61fc6c7c..291c412b 100644
--- a/jupyterhub/utils.py
+++ b/jupyterhub/utils.py
@@ -527,7 +527,6 @@ def print_stacks(file=sys.stderr):
     """
     # local imports because these will not be used often,
     # no need to add them to startup
-    import asyncio
     import traceback
 
     from .log import coroutine_frames