diff --git a/docs/conf.py b/docs/conf.py
index 6e17794..4fe8992 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -133,7 +133,7 @@
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = []
+html_static_path: list[str] = []
 
 # If not "", a "Last updated on:" timestamp is inserted at every page bottom,
 # using the given strftime format.
@@ -182,14 +182,14 @@
 
 # -- Options for LaTeX output --------------------------------------------------
 
-latex_elements = {
-    # The paper size ("letterpaper" or "a4paper").
-    # "papersize": "letterpaper",
-    # The font size ("10pt", "11pt" or "12pt").
-    # "pointsize": "10pt",
-    # Additional stuff for the LaTeX preamble.
-    # "preamble": "",
-}
+# latex_elements = {
+# The paper size ("letterpaper" or "a4paper").
+# "papersize": "letterpaper",
+# The font size ("10pt", "11pt" or "12pt").
+# "pointsize": "10pt",
+# Additional stuff for the LaTeX preamble.
+# "preamble": "",
+# }
 
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title, author, documentclass [howto/manual]).
@@ -228,9 +228,7 @@
 
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
-man_pages = [
-    ("index", "flask-pymongo", "Flask-PyMongo Documentation", ["Dan Crosta"], 1)
-]
+man_pages = [("index", "flask-pymongo", "Flask-PyMongo Documentation", ["Dan Crosta"], 1)]
 
 # If true, show URL addresses after external links.
 # man_show_urls = False
diff --git a/examples/wiki/wiki.py b/examples/wiki/wiki.py
index b4b64ec..ed29fda 100644
--- a/examples/wiki/wiki.py
+++ b/examples/wiki/wiki.py
@@ -1,12 +1,16 @@
 from __future__ import annotations
 
 import re
+from typing import TYPE_CHECKING, Any
 
-import markdown2
+import markdown2  # type:ignore[import-untyped]
 from flask import Flask, redirect, render_template, request, url_for
 
 from flask_pymongo import PyMongo
 
+if TYPE_CHECKING:
+    from werkzeug.wrappers.response import Response
+
 app = Flask(__name__)
 mongo = PyMongo(app, "mongodb://localhost/wiki")
 
@@ -15,17 +19,17 @@
 
 
 @app.route("/", methods=["GET"])
-def redirect_to_homepage():
+def redirect_to_homepage() -> Response:
     return redirect(url_for("show_page", pagepath="HomePage"))
 
 
 @app.template_filter()
-def totitle(value):
+def totitle(value: str) -> str:
     return " ".join(WIKIPART.findall(value))
 
 
 @app.template_filter()
-def wikify(value):
+def wikify(value: str) -> Any:
     parts = WIKIWORD.split(value)
     for i, part in enumerate(parts):
         if WIKIWORD.match(part):
@@ -36,20 +40,23 @@ def wikify(value):
 
 
 @app.route("/<path:pagepath>")
-def show_page(pagepath):
-    page = mongo.db.pages.find_one_or_404({"_id": pagepath})
+def show_page(pagepath: str) -> str:
+    assert mongo.db is not None
+    page: dict[str, Any] = mongo.db.pages.find_one_or_404({"_id": pagepath})
     return render_template("page.html", page=page, pagepath=pagepath)
 
 
 @app.route("/edit/<path:pagepath>", methods=["GET"])
-def edit_page(pagepath):
-    page = mongo.db.pages.find_one_or_404({"_id": pagepath})
+def edit_page(pagepath: str) -> str:
+    assert mongo.db is not None
+    page: dict[str, Any] = mongo.db.pages.find_one_or_404({"_id": pagepath})
     return render_template("edit.html", page=page, pagepath=pagepath)
 
 
 @app.route("/edit/<path:pagepath>", methods=["POST"])
-def save_page(pagepath):
+def save_page(pagepath: str) -> Response:
     if "cancel" not in request.form:
+        assert mongo.db is not None
         mongo.db.pages.update(
             {"_id": pagepath},
             {"$set": {"body": request.form["body"]}},
@@ -60,7 +67,7 @@ def save_page(pagepath):
 
 
 @app.errorhandler(404)
-def new_page(error):
+def new_page(error: Any) -> str:
     pagepath = request.path.lstrip("/")
     if pagepath.startswith("uploads"):
         filename = pagepath[len("uploads") :].lstrip("/")
@@ -69,12 +76,12 @@ def new_page(error):
 
 
 @app.route("/uploads/<path:filename>")
-def get_upload(filename):
+def get_upload(filename: str) -> Response:
     return mongo.send_file(filename)
 
 
 @app.route("/uploads/<path:filename>", methods=["POST"])
-def save_upload(filename):
+def save_upload(filename: str) -> str | Response:
     if request.files.get("file"):
         mongo.save_file(filename, request.files["file"])
         return redirect(url_for("get_upload", filename=filename))
diff --git a/flask_pymongo/__init__.py b/flask_pymongo/__init__.py
index e1de50c..72aef75 100644
--- a/flask_pymongo/__init__.py
+++ b/flask_pymongo/__init__.py
@@ -24,26 +24,22 @@
 # POSSIBILITY OF SUCH DAMAGE.
 from __future__ import annotations
 
-__all__ = ("PyMongo", "ASCENDING", "DESCENDING")
+__all__ = ("PyMongo", "ASCENDING", "DESCENDING", "BSONObjectIdConverter", "BSONProvider")
 
 import hashlib
 from mimetypes import guess_type
+from typing import Any
 
 import pymongo
-from flask import abort, current_app, request
+from flask import Flask, Response, abort, current_app, request
 from gridfs import GridFS, NoFile
 from pymongo import uri_parser
+from pymongo.driver_info import DriverInfo
 from werkzeug.wsgi import wrap_file
 
-# DriverInfo was added in PyMongo 3.7
-try:
-    from pymongo.driver_info import DriverInfo
-except ImportError:
-    DriverInfo = None
-
 from flask_pymongo._version import __version__
 from flask_pymongo.helpers import BSONObjectIdConverter, BSONProvider
-from flask_pymongo.wrappers import MongoClient
+from flask_pymongo.wrappers import Database, MongoClient
 
 DESCENDING = pymongo.DESCENDING
 """Descending sort order."""
@@ -65,15 +61,16 @@ class PyMongo:
 
     """
 
-    def __init__(self, app=None, uri=None, *args, **kwargs):
-        self.cx = None
-        self.db = None
-        self._json_provider = BSONProvider(app)
+    def __init__(
+        self, app: Flask | None = None, uri: str | None = None, *args: Any, **kwargs: Any
+    ) -> None:
+        self.cx: MongoClient | None = None
+        self.db: Database | None = None
 
         if app is not None:
             self.init_app(app, uri, *args, **kwargs)
 
-    def init_app(self, app, uri=None, *args, **kwargs):
+    def init_app(self, app: Flask, uri: str | None = None, *args: Any, **kwargs: Any) -> None:
         """Initialize this :class:`PyMongo` for use.
 
         Configure a :class:`~pymongo.mongo_client.MongoClient`
@@ -122,10 +119,12 @@ def init_app(self, app, uri=None, *args, **kwargs):
             self.db = self.cx[database_name]
 
         app.url_map.converters["ObjectId"] = BSONObjectIdConverter
-        app.json = self._json_provider
+        app.json = BSONProvider(app)
 
     # view helpers
-    def send_file(self, filename, base="fs", version=-1, cache_for=31536000):
+    def send_file(
+        self, filename: str, base: str = "fs", version: int = -1, cache_for: int = 31536000
+    ) -> Response:
         """Respond with a file from GridFS.
 
         Returns an instance of the :attr:`~flask.Flask.response_class`
@@ -153,6 +152,7 @@ def get_upload(filename):
         if not isinstance(cache_for, int):
             raise TypeError("'cache_for' must be an integer")
 
+        assert self.db is not None, "Please initialize the app before calling send_file!"
         storage = GridFS(self.db, base)
 
         try:
@@ -183,7 +183,14 @@ def get_upload(filename):
         response.make_conditional(request)
         return response
 
-    def save_file(self, filename, fileobj, base="fs", content_type=None, **kwargs):
+    def save_file(
+        self,
+        filename: str,
+        fileobj: Any,
+        base: str = "fs",
+        content_type: str | None = None,
+        **kwargs: Any,
+    ) -> Any:
         """Save a file-like object to GridFS using the given filename.
            Return the "_id" of the created file.
 
@@ -211,8 +218,7 @@ def save_upload(filename):
         if content_type is None:
             content_type, _ = guess_type(filename)
 
+        assert self.db is not None, "Please initialize the app before calling save_file!"
         storage = GridFS(self.db, base)
-        id = storage.put(
-            fileobj, filename=filename, content_type=content_type, **kwargs
-        )
+        id = storage.put(fileobj, filename=filename, content_type=content_type, **kwargs)
         return id
diff --git a/flask_pymongo/helpers.py b/flask_pymongo/helpers.py
index 2660562..ed09d11 100644
--- a/flask_pymongo/helpers.py
+++ b/flask_pymongo/helpers.py
@@ -26,6 +26,8 @@
 
 __all__ = ("BSONObjectIdConverter", "BSONProvider")
 
+from typing import Any
+
 from bson import json_util
 from bson.errors import InvalidId
 from bson.json_util import RELAXED_JSON_OPTIONS
@@ -35,7 +37,7 @@
 from werkzeug.routing import BaseConverter
 
 
-def _iteritems(obj):
+def _iteritems(obj: Any) -> Any:
     if hasattr(obj, "iteritems"):
         return obj.iteritems()
     if hasattr(obj, "items"):
@@ -65,13 +67,13 @@ def show_task(task_id):
 
     """
 
-    def to_python(self, value):
+    def to_python(self, value: Any) -> ObjectId:
         try:
             return ObjectId(value)
         except InvalidId:
             raise abort(404) from None
 
-    def to_url(self, value):
+    def to_url(self, value: Any) -> str:
         return str(value)
 
 
@@ -98,15 +100,15 @@ def json_route(cart_id):
     :const:`~bson.json_util.RELAXED_JSON_OPTIONS`.
     """
 
-    def __init__(self, app):
+    def __init__(self, app: Any) -> None:
         self._default_kwargs = {"json_options": RELAXED_JSON_OPTIONS}
 
         super().__init__(app)
 
-    def dumps(self, obj):
+    def dumps(self, obj: Any, **kwargs: Any) -> str:
         """Serialize MongoDB object types using :mod:`bson.json_util`."""
         return json_util.dumps(obj)
 
-    def loads(self, str_obj):
+    def loads(self, s: str | bytes, **kwargs: Any) -> Any:
         """Deserialize MongoDB object types using :mod:`bson.json_util`."""
-        return json_util.loads(str_obj)
+        return json_util.loads(s)
diff --git a/flask_pymongo/tests/__init__.py b/flask_pymongo/py.typed
similarity index 100%
rename from flask_pymongo/tests/__init__.py
rename to flask_pymongo/py.typed
diff --git a/flask_pymongo/wrappers.py b/flask_pymongo/wrappers.py
index dd30d49..fc543df 100644
--- a/flask_pymongo/wrappers.py
+++ b/flask_pymongo/wrappers.py
@@ -24,11 +24,13 @@
 # POSSIBILITY OF SUCH DAMAGE.
 from __future__ import annotations
 
+from typing import Any
+
 from flask import abort
 from pymongo import collection, database, mongo_client
 
 
-class MongoClient(mongo_client.MongoClient):
+class MongoClient(mongo_client.MongoClient[dict[str, Any]]):
     """Wrapper for :class:`~pymongo.mongo_client.MongoClient`.
 
     Returns instances of Flask-PyMongo
@@ -37,20 +39,20 @@ class MongoClient(mongo_client.MongoClient):
 
     """
 
-    def __getattr__(self, name):
+    def __getattr__(self, name: str) -> Any:
         attr = super().__getattr__(name)
         if isinstance(attr, database.Database):
             return Database(self, name)
         return attr
 
-    def __getitem__(self, item):
-        attr = super().__getitem__(item)
+    def __getitem__(self, name: str) -> Any:
+        attr = super().__getitem__(name)
         if isinstance(attr, database.Database):
-            return Database(self, item)
+            return Database(self, name)
         return attr
 
 
-class Database(database.Database):
+class Database(database.Database[dict[str, Any]]):
     """Wrapper for :class:`~pymongo.database.Database`.
 
     Returns instances of Flask-PyMongo
@@ -59,37 +61,37 @@ class Database(database.Database):
 
     """
 
-    def __getattr__(self, name):
+    def __getattr__(self, name: str) -> Any:
         attr = super().__getattr__(name)
         if isinstance(attr, collection.Collection):
             return Collection(self, name)
         return attr
 
-    def __getitem__(self, item):
-        item_ = super().__getitem__(item)
+    def __getitem__(self, name: str) -> Any:
+        item_ = super().__getitem__(name)
         if isinstance(item_, collection.Collection):
-            return Collection(self, item)
+            return Collection(self, name)
         return item_
 
 
-class Collection(collection.Collection):
+class Collection(collection.Collection[dict[str, Any]]):
     """Sub-class of PyMongo :class:`~pymongo.collection.Collection` with helpers."""
 
-    def __getattr__(self, name):
+    def __getattr__(self, name: str) -> Any:
         attr = super().__getattr__(name)
         if isinstance(attr, collection.Collection):
             db = self._Collection__database
             return Collection(db, attr.name)
         return attr
 
-    def __getitem__(self, item):
-        item_ = super().__getitem__(item)
-        if isinstance(item_, collection.Collection):
+    def __getitem__(self, name: str) -> Any:
+        item = super().__getitem__(name)
+        if isinstance(item, collection.Collection):
             db = self._Collection__database
-            return Collection(db, item_.name)
-        return item_
+            return Collection(db, item.name)
+        return item
 
-    def find_one_or_404(self, *args, **kwargs):
+    def find_one_or_404(self, *args: Any, **kwargs: Any) -> Any:
         """Find a single document or raise a 404.
 
         This is like :meth:`~pymongo.collection.Collection.find_one`, but
diff --git a/justfile b/justfile
index cd2a9f5..e5fc302 100644
--- a/justfile
+++ b/justfile
@@ -16,3 +16,6 @@ lint:
 
 docs:
     uv run sphinx-build -T -b html docs docs/_build
+
+typing:
+    uv run mypy --install-types --non-interactive .
diff --git a/pyproject.toml b/pyproject.toml
index 26264e0..bcc9b12 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -37,6 +37,15 @@ dependencies = [
 Download = "https://github.com/mongodb-labs/flask-pymongo/tags"
 Homepage = "http://flask-pymongo.readthedocs.org/"
 
+[dependency-groups]
+dev = [
+    "markdown2>=2.5.2",
+    "mypy>=1.14.1",
+    "pre-commit>=4.0.1",
+    "pytest>=8.3.4",
+    "sphinx>=7.4.7",
+]
+
 [tool.hatch.version]
 path = "flask_pymongo/_version.py"
 
@@ -45,6 +54,18 @@ include = [
     "/flask_pymongo",
 ]
 
+[tool.mypy]
+python_version = "3.9"
+strict = true
+enable_error_code = ["ignore-without-code", "redundant-expr", "truthy-bool"]
+
+[[tool.mypy.overrides]]
+module = ["tests.*"]
+disable_error_code = ["no-untyped-def", "no-untyped-call"]
+
+[tool.ruff]
+line-length = 100
+
 [tool.ruff.lint]
 select = [
   "E",  # pycodestyle
@@ -58,11 +79,3 @@ unfixable = [
   "T20",  # Removes print statements
   "F401",  # Unused imports
 ]
-
-[dependency-groups]
-dev = [
-    "markdown2>=2.5.2",
-    "pre-commit>=4.0.1",
-    "pytest>=8.3.4",
-    "sphinx>=7.4.7",
-]
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/flask_pymongo/tests/test_config.py b/tests/test_config.py
similarity index 87%
rename from flask_pymongo/tests/test_config.py
rename to tests/test_config.py
index 9667da0..ddf5fe3 100644
--- a/flask_pymongo/tests/test_config.py
+++ b/tests/test_config.py
@@ -2,12 +2,14 @@
 
 import time
 from contextlib import contextmanager
+from typing import Any
 
 import pymongo
 import pytest
 
 import flask_pymongo
-from flask_pymongo.tests.util import FlaskRequestTest
+
+from .util import FlaskRequestTest
 
 
 class CouldNotConnect(Exception):
@@ -26,16 +28,18 @@ class FlaskPyMongoConfigTest(FlaskRequestTest):
     def setUp(self):
         super().setUp()
 
-        conn = pymongo.MongoClient(port=self.port)
+        conn: pymongo.MongoClient[Any] = pymongo.MongoClient(port=self.port)
         conn.test.command("ping")  # wait for server
+        conn.close()
 
     def tearDown(self):
         super().tearDown()
 
-        conn = pymongo.MongoClient(port=self.port)
+        conn: pymongo.MongoClient[Any] = pymongo.MongoClient(port=self.port)
 
         conn.drop_database(self.dbname)
         conn.drop_database(self.dbname + "2")
+        conn.close()
 
     def test_config_with_uri_in_flask_conf_var(self):
         uri = f"mongodb://localhost:{self.port}/{self.dbname}"
@@ -44,6 +48,8 @@ def test_config_with_uri_in_flask_conf_var(self):
         mongo = flask_pymongo.PyMongo(self.app, connect=True)
 
         _wait_until_connected(mongo)
+        assert mongo.db is not None
+        assert mongo.cx is not None
         assert mongo.db.name == self.dbname
         assert ("localhost", self.port) == mongo.cx.address or (
             "127.0.0.1",
@@ -56,6 +62,8 @@ def test_config_with_uri_passed_directly(self):
         mongo = flask_pymongo.PyMongo(self.app, uri, connect=True)
 
         _wait_until_connected(mongo)
+        assert mongo.db is not None
+        assert mongo.cx is not None
         assert mongo.db.name == self.dbname
         assert ("localhost", self.port) == mongo.cx.address or (
             "127.0.0.1",
@@ -78,11 +86,12 @@ def test_multiple_pymongos(self):
         # this test passes if it raises no exceptions
 
     def test_custom_document_class(self):
-        class CustomDict(dict):
+        class CustomDict(dict[str, Any]):
             pass
 
         uri = f"mongodb://localhost:{self.port}/{self.dbname}"
         mongo = flask_pymongo.PyMongo(self.app, uri, document_class=CustomDict)
+        assert mongo.db is not None
         assert mongo.db.things.find_one() is None, "precondition failed"
 
         mongo.db.things.insert_one({"_id": "thing", "val": "foo"})
diff --git a/flask_pymongo/tests/test_gridfs.py b/tests/test_gridfs.py
similarity index 90%
rename from flask_pymongo/tests/test_gridfs.py
rename to tests/test_gridfs.py
index c778167..93a6672 100644
--- a/flask_pymongo/tests/test_gridfs.py
+++ b/tests/test_gridfs.py
@@ -8,17 +8,17 @@
 from gridfs import GridFS
 from werkzeug.exceptions import NotFound
 
-from flask_pymongo.tests.util import FlaskPyMongoTest
+from .util import FlaskPyMongoTest
 
 
 class GridFSCleanupMixin:
     def tearDown(self):
-        gridfs = GridFS(self.mongo.db)
+        gridfs = GridFS(self.mongo.db)  # type:ignore[attr-defined]
         files = list(gridfs.find())
         for gridfile in files:
             gridfs.delete(gridfile._id)
 
-        super().tearDown()
+        super().tearDown()  # type:ignore[misc]
 
 
 class TestSaveFile(GridFSCleanupMixin, FlaskPyMongoTest):
@@ -26,7 +26,7 @@ def test_it_saves_files(self):
         fileobj = BytesIO(b"these are the bytes")
 
         self.mongo.save_file("my-file", fileobj)
-
+        assert self.mongo.db is not None
         gridfs = GridFS(self.mongo.db)
         assert gridfs.exists({"filename": "my-file"})
 
@@ -35,8 +35,10 @@ def test_it_saves_files_with_props(self):
 
         self.mongo.save_file("my-file", fileobj, foo="bar")
 
+        assert self.mongo.db is not None
         gridfs = GridFS(self.mongo.db)
         gridfile = gridfs.find_one({"filename": "my-file"})
+        assert gridfile is not None
         assert gridfile.foo == "bar"
 
     def test_it_returns_id(self):
diff --git a/flask_pymongo/tests/test_json.py b/tests/test_json.py
similarity index 92%
rename from flask_pymongo/tests/test_json.py
rename to tests/test_json.py
index 424d7b5..753d624 100644
--- a/flask_pymongo/tests/test_json.py
+++ b/tests/test_json.py
@@ -5,7 +5,7 @@
 from bson import ObjectId
 from flask import jsonify
 
-from flask_pymongo.tests.util import FlaskPyMongoTest
+from .util import FlaskPyMongoTest
 
 
 class JSONTest(FlaskPyMongoTest):
@@ -20,8 +20,8 @@ def test_it_handles_pymongo_types(self):
         self.assertEqual(dumped, {"id": {"$oid": "5cf29abb5167a14c9e6e12c4"}})
 
     def test_it_jsonifies_a_cursor(self):
+        assert self.mongo.db is not None
         self.mongo.db.rows.insert_many([{"foo": "bar"}, {"foo": "baz"}])
-
         curs = self.mongo.db.rows.find(projection={"_id": False}).sort("foo")
 
         resp = jsonify(curs)
diff --git a/flask_pymongo/tests/test_url_converter.py b/tests/test_url_converter.py
similarity index 64%
rename from flask_pymongo/tests/test_url_converter.py
rename to tests/test_url_converter.py
index a7e4950..46b4bc2 100644
--- a/flask_pymongo/tests/test_url_converter.py
+++ b/tests/test_url_converter.py
@@ -2,20 +2,19 @@
 
 from bson import ObjectId
 from werkzeug.exceptions import NotFound
+from werkzeug.routing.map import Map
 
 from flask_pymongo import BSONObjectIdConverter
-from flask_pymongo.tests.util import FlaskPyMongoTest
+
+from .util import FlaskPyMongoTest
 
 
 class UrlConverterTest(FlaskPyMongoTest):
     def test_bson_object_id_converter(self):
-        converter = BSONObjectIdConverter("/")
+        converter = BSONObjectIdConverter(Map())
 
         self.assertRaises(NotFound, converter.to_python, ("132"))
         assert converter.to_python("4e4ac5cfffc84958fa1f45fb") == ObjectId(
             "4e4ac5cfffc84958fa1f45fb"
         )
-        assert (
-            converter.to_url(ObjectId("4e4ac5cfffc84958fa1f45fb"))
-            == "4e4ac5cfffc84958fa1f45fb"
-        )
+        assert converter.to_url(ObjectId("4e4ac5cfffc84958fa1f45fb")) == "4e4ac5cfffc84958fa1f45fb"
diff --git a/flask_pymongo/tests/test_wrappers.py b/tests/test_wrappers.py
similarity index 69%
rename from flask_pymongo/tests/test_wrappers.py
rename to tests/test_wrappers.py
index ca87b13..39af363 100644
--- a/flask_pymongo/tests/test_wrappers.py
+++ b/tests/test_wrappers.py
@@ -1,12 +1,15 @@
 from __future__ import annotations
 
+from typing import Any
+
 from werkzeug.exceptions import HTTPException
 
-from flask_pymongo.tests.util import FlaskPyMongoTest
+from .util import FlaskPyMongoTest
 
 
 class CollectionTest(FlaskPyMongoTest):
     def test_find_one_or_404(self):
+        assert self.mongo.db is not None
         self.mongo.db.things.delete_many({})
 
         try:
@@ -17,5 +20,5 @@ def test_find_one_or_404(self):
         self.mongo.db.things.insert_one({"_id": "thing", "val": "foo"})
 
         # now it should not raise
-        thing = self.mongo.db.things.find_one_or_404({"_id": "thing"})
-        assert thing["val"] == "foo", "got wrong thing"
+        thing: dict[str, Any] = self.mongo.db.things.find_one_or_404({"_id": "thing"})
+        assert thing["val"] == "foo"
diff --git a/flask_pymongo/tests/util.py b/tests/util.py
similarity index 94%
rename from flask_pymongo/tests/util.py
rename to tests/util.py
index 7372e16..9f2ab83 100644
--- a/flask_pymongo/tests/util.py
+++ b/tests/util.py
@@ -31,6 +31,7 @@ def setUp(self):
         self.mongo = flask_pymongo.PyMongo(self.app, uri)
 
     def tearDown(self):
+        assert self.mongo.cx is not None
         self.mongo.cx.drop_database(self.dbname)
 
         super().tearDown()
diff --git a/uv.lock b/uv.lock
index 327029b..b1c40c1 100644
--- a/uv.lock
+++ b/uv.lock
@@ -234,6 +234,7 @@ dependencies = [
 [package.dev-dependencies]
 dev = [
     { name = "markdown2" },
+    { name = "mypy" },
     { name = "pre-commit" },
     { name = "pytest" },
     { name = "sphinx", version = "7.4.7", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
@@ -249,6 +250,7 @@ requires-dist = [
 [package.metadata.requires-dev]
 dev = [
     { name = "markdown2", specifier = ">=2.5.2" },
+    { name = "mypy", specifier = ">=1.14.1" },
     { name = "pre-commit", specifier = ">=4.0.1" },
     { name = "pytest", specifier = ">=8.3.4" },
     { name = "sphinx", specifier = ">=7.4.7" },
@@ -400,6 +402,59 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/b3/73/085399401383ce949f727afec55ec3abd76648d04b9f22e1c0e99cb4bec3/MarkupSafe-3.0.2-cp39-cp39-win_amd64.whl", hash = "sha256:6e296a513ca3d94054c2c881cc913116e90fd030ad1c656b3869762b754f5f8a", size = 15506 },
 ]
 
+[[package]]
+name = "mypy"
+version = "1.14.1"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "mypy-extensions" },
+    { name = "tomli", marker = "python_full_version < '3.11'" },
+    { name = "typing-extensions" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/b9/eb/2c92d8ea1e684440f54fa49ac5d9a5f19967b7b472a281f419e69a8d228e/mypy-1.14.1.tar.gz", hash = "sha256:7ec88144fe9b510e8475ec2f5f251992690fcf89ccb4500b214b4226abcd32d6", size = 3216051 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/9b/7a/87ae2adb31d68402da6da1e5f30c07ea6063e9f09b5e7cfc9dfa44075e74/mypy-1.14.1-cp310-cp310-macosx_10_9_x86_64.whl", hash = "sha256:52686e37cf13d559f668aa398dd7ddf1f92c5d613e4f8cb262be2fb4fedb0fcb", size = 11211002 },
+    { url = "https://files.pythonhosted.org/packages/e1/23/eada4c38608b444618a132be0d199b280049ded278b24cbb9d3fc59658e4/mypy-1.14.1-cp310-cp310-macosx_11_0_arm64.whl", hash = "sha256:1fb545ca340537d4b45d3eecdb3def05e913299ca72c290326be19b3804b39c0", size = 10358400 },
+    { url = "https://files.pythonhosted.org/packages/43/c9/d6785c6f66241c62fd2992b05057f404237deaad1566545e9f144ced07f5/mypy-1.14.1-cp310-cp310-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_28_aarch64.whl", hash = "sha256:90716d8b2d1f4cd503309788e51366f07c56635a3309b0f6a32547eaaa36a64d", size = 12095172 },
+    { url = "https://files.pythonhosted.org/packages/c3/62/daa7e787770c83c52ce2aaf1a111eae5893de9e004743f51bfcad9e487ec/mypy-1.14.1-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_28_x86_64.whl", hash = "sha256:2ae753f5c9fef278bcf12e1a564351764f2a6da579d4a81347e1d5a15819997b", size = 12828732 },
+    { url = "https://files.pythonhosted.org/packages/1b/a2/5fb18318a3637f29f16f4e41340b795da14f4751ef4f51c99ff39ab62e52/mypy-1.14.1-cp310-cp310-musllinux_1_2_x86_64.whl", hash = "sha256:e0fe0f5feaafcb04505bcf439e991c6d8f1bf8b15f12b05feeed96e9e7bf1427", size = 13012197 },
+    { url = "https://files.pythonhosted.org/packages/28/99/e153ce39105d164b5f02c06c35c7ba958aaff50a2babba7d080988b03fe7/mypy-1.14.1-cp310-cp310-win_amd64.whl", hash = "sha256:7d54bd85b925e501c555a3227f3ec0cfc54ee8b6930bd6141ec872d1c572f81f", size = 9780836 },
+    { url = "https://files.pythonhosted.org/packages/da/11/a9422850fd506edbcdc7f6090682ecceaf1f87b9dd847f9df79942da8506/mypy-1.14.1-cp311-cp311-macosx_10_9_x86_64.whl", hash = "sha256:f995e511de847791c3b11ed90084a7a0aafdc074ab88c5a9711622fe4751138c", size = 11120432 },
+    { url = "https://files.pythonhosted.org/packages/b6/9e/47e450fd39078d9c02d620545b2cb37993a8a8bdf7db3652ace2f80521ca/mypy-1.14.1-cp311-cp311-macosx_11_0_arm64.whl", hash = "sha256:d64169ec3b8461311f8ce2fd2eb5d33e2d0f2c7b49116259c51d0d96edee48d1", size = 10279515 },
+    { url = "https://files.pythonhosted.org/packages/01/b5/6c8d33bd0f851a7692a8bfe4ee75eb82b6983a3cf39e5e32a5d2a723f0c1/mypy-1.14.1-cp311-cp311-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_28_aarch64.whl", hash = "sha256:ba24549de7b89b6381b91fbc068d798192b1b5201987070319889e93038967a8", size = 12025791 },
+    { url = "https://files.pythonhosted.org/packages/f0/4c/e10e2c46ea37cab5c471d0ddaaa9a434dc1d28650078ac1b56c2d7b9b2e4/mypy-1.14.1-cp311-cp311-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_28_x86_64.whl", hash = "sha256:183cf0a45457d28ff9d758730cd0210419ac27d4d3f285beda038c9083363b1f", size = 12749203 },
+    { url = "https://files.pythonhosted.org/packages/88/55/beacb0c69beab2153a0f57671ec07861d27d735a0faff135a494cd4f5020/mypy-1.14.1-cp311-cp311-musllinux_1_2_x86_64.whl", hash = "sha256:f2a0ecc86378f45347f586e4163d1769dd81c5a223d577fe351f26b179e148b1", size = 12885900 },
+    { url = "https://files.pythonhosted.org/packages/a2/75/8c93ff7f315c4d086a2dfcde02f713004357d70a163eddb6c56a6a5eff40/mypy-1.14.1-cp311-cp311-win_amd64.whl", hash = "sha256:ad3301ebebec9e8ee7135d8e3109ca76c23752bac1e717bc84cd3836b4bf3eae", size = 9777869 },
+    { url = "https://files.pythonhosted.org/packages/43/1b/b38c079609bb4627905b74fc6a49849835acf68547ac33d8ceb707de5f52/mypy-1.14.1-cp312-cp312-macosx_10_13_x86_64.whl", hash = "sha256:30ff5ef8519bbc2e18b3b54521ec319513a26f1bba19a7582e7b1f58a6e69f14", size = 11266668 },
+    { url = "https://files.pythonhosted.org/packages/6b/75/2ed0d2964c1ffc9971c729f7a544e9cd34b2cdabbe2d11afd148d7838aa2/mypy-1.14.1-cp312-cp312-macosx_11_0_arm64.whl", hash = "sha256:cb9f255c18052343c70234907e2e532bc7e55a62565d64536dbc7706a20b78b9", size = 10254060 },
+    { url = "https://files.pythonhosted.org/packages/a1/5f/7b8051552d4da3c51bbe8fcafffd76a6823779101a2b198d80886cd8f08e/mypy-1.14.1-cp312-cp312-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_28_aarch64.whl", hash = "sha256:8b4e3413e0bddea671012b063e27591b953d653209e7a4fa5e48759cda77ca11", size = 11933167 },
+    { url = "https://files.pythonhosted.org/packages/04/90/f53971d3ac39d8b68bbaab9a4c6c58c8caa4d5fd3d587d16f5927eeeabe1/mypy-1.14.1-cp312-cp312-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_28_x86_64.whl", hash = "sha256:553c293b1fbdebb6c3c4030589dab9fafb6dfa768995a453d8a5d3b23784af2e", size = 12864341 },
+    { url = "https://files.pythonhosted.org/packages/03/d2/8bc0aeaaf2e88c977db41583559319f1821c069e943ada2701e86d0430b7/mypy-1.14.1-cp312-cp312-musllinux_1_2_x86_64.whl", hash = "sha256:fad79bfe3b65fe6a1efaed97b445c3d37f7be9fdc348bdb2d7cac75579607c89", size = 12972991 },
+    { url = "https://files.pythonhosted.org/packages/6f/17/07815114b903b49b0f2cf7499f1c130e5aa459411596668267535fe9243c/mypy-1.14.1-cp312-cp312-win_amd64.whl", hash = "sha256:8fa2220e54d2946e94ab6dbb3ba0a992795bd68b16dc852db33028df2b00191b", size = 9879016 },
+    { url = "https://files.pythonhosted.org/packages/9e/15/bb6a686901f59222275ab228453de741185f9d54fecbaacec041679496c6/mypy-1.14.1-cp313-cp313-macosx_10_13_x86_64.whl", hash = "sha256:92c3ed5afb06c3a8e188cb5da4984cab9ec9a77ba956ee419c68a388b4595255", size = 11252097 },
+    { url = "https://files.pythonhosted.org/packages/f8/b3/8b0f74dfd072c802b7fa368829defdf3ee1566ba74c32a2cb2403f68024c/mypy-1.14.1-cp313-cp313-macosx_11_0_arm64.whl", hash = "sha256:dbec574648b3e25f43d23577309b16534431db4ddc09fda50841f1e34e64ed34", size = 10239728 },
+    { url = "https://files.pythonhosted.org/packages/c5/9b/4fd95ab20c52bb5b8c03cc49169be5905d931de17edfe4d9d2986800b52e/mypy-1.14.1-cp313-cp313-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_28_aarch64.whl", hash = "sha256:8c6d94b16d62eb3e947281aa7347d78236688e21081f11de976376cf010eb31a", size = 11924965 },
+    { url = "https://files.pythonhosted.org/packages/56/9d/4a236b9c57f5d8f08ed346914b3f091a62dd7e19336b2b2a0d85485f82ff/mypy-1.14.1-cp313-cp313-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_28_x86_64.whl", hash = "sha256:d4b19b03fdf54f3c5b2fa474c56b4c13c9dbfb9a2db4370ede7ec11a2c5927d9", size = 12867660 },
+    { url = "https://files.pythonhosted.org/packages/40/88/a61a5497e2f68d9027de2bb139c7bb9abaeb1be1584649fa9d807f80a338/mypy-1.14.1-cp313-cp313-musllinux_1_2_x86_64.whl", hash = "sha256:0c911fde686394753fff899c409fd4e16e9b294c24bfd5e1ea4675deae1ac6fd", size = 12969198 },
+    { url = "https://files.pythonhosted.org/packages/54/da/3d6fc5d92d324701b0c23fb413c853892bfe0e1dbe06c9138037d459756b/mypy-1.14.1-cp313-cp313-win_amd64.whl", hash = "sha256:8b21525cb51671219f5307be85f7e646a153e5acc656e5cebf64bfa076c50107", size = 9885276 },
+    { url = "https://files.pythonhosted.org/packages/ca/1f/186d133ae2514633f8558e78cd658070ba686c0e9275c5a5c24a1e1f0d67/mypy-1.14.1-cp39-cp39-macosx_10_9_x86_64.whl", hash = "sha256:3888a1816d69f7ab92092f785a462944b3ca16d7c470d564165fe703b0970c35", size = 11200493 },
+    { url = "https://files.pythonhosted.org/packages/af/fc/4842485d034e38a4646cccd1369f6b1ccd7bc86989c52770d75d719a9941/mypy-1.14.1-cp39-cp39-macosx_11_0_arm64.whl", hash = "sha256:46c756a444117c43ee984bd055db99e498bc613a70bbbc120272bd13ca579fbc", size = 10357702 },
+    { url = "https://files.pythonhosted.org/packages/b4/e6/457b83f2d701e23869cfec013a48a12638f75b9d37612a9ddf99072c1051/mypy-1.14.1-cp39-cp39-manylinux_2_17_aarch64.manylinux2014_aarch64.manylinux_2_28_aarch64.whl", hash = "sha256:27fc248022907e72abfd8e22ab1f10e903915ff69961174784a3900a8cba9ad9", size = 12091104 },
+    { url = "https://files.pythonhosted.org/packages/f1/bf/76a569158db678fee59f4fd30b8e7a0d75bcbaeef49edd882a0d63af6d66/mypy-1.14.1-cp39-cp39-manylinux_2_17_x86_64.manylinux2014_x86_64.manylinux_2_28_x86_64.whl", hash = "sha256:499d6a72fb7e5de92218db961f1a66d5f11783f9ae549d214617edab5d4dbdbb", size = 12830167 },
+    { url = "https://files.pythonhosted.org/packages/43/bc/0bc6b694b3103de9fed61867f1c8bd33336b913d16831431e7cb48ef1c92/mypy-1.14.1-cp39-cp39-musllinux_1_2_x86_64.whl", hash = "sha256:57961db9795eb566dc1d1b4e9139ebc4c6b0cb6e7254ecde69d1552bf7613f60", size = 13013834 },
+    { url = "https://files.pythonhosted.org/packages/b0/79/5f5ec47849b6df1e6943d5fd8e6632fbfc04b4fd4acfa5a5a9535d11b4e2/mypy-1.14.1-cp39-cp39-win_amd64.whl", hash = "sha256:07ba89fdcc9451f2ebb02853deb6aaaa3d2239a236669a63ab3801bbf923ef5c", size = 9781231 },
+    { url = "https://files.pythonhosted.org/packages/a0/b5/32dd67b69a16d088e533962e5044e51004176a9952419de0370cdaead0f8/mypy-1.14.1-py3-none-any.whl", hash = "sha256:b66a60cc4073aeb8ae00057f9c1f64d49e90f918fbcef9a977eb121da8b8f1d1", size = 2752905 },
+]
+
+[[package]]
+name = "mypy-extensions"
+version = "1.0.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/98/a4/1ab47638b92648243faf97a5aeb6ea83059cc3624972ab6b8d2316078d3f/mypy_extensions-1.0.0.tar.gz", hash = "sha256:75dbf8955dc00442a438fc4d0666508a9a97b6bd41aa2f0ffe9d2f2725af0782", size = 4433 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/2a/e2/5d3f6ada4297caebe1a2add3b126fe800c96f56dbe5d1988a2cbe0b267aa/mypy_extensions-1.0.0-py3-none-any.whl", hash = "sha256:4392f6c0eb8a5668a69e23d168ffa70f0be9ccfd32b5cc2d26a34ae5b844552d", size = 4695 },
+]
+
 [[package]]
 name = "nodeenv"
 version = "1.9.1"
@@ -769,6 +824,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/6e/c2/61d3e0f47e2b74ef40a68b9e6ad5984f6241a942f7cd3bbfbdbd03861ea9/tomli-2.2.1-py3-none-any.whl", hash = "sha256:cb55c73c5f4408779d0cf3eef9f762b9c9f147a77de7b258bef0a5628adc85cc", size = 14257 },
 ]
 
+[[package]]
+name = "typing-extensions"
+version = "4.12.2"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/df/db/f35a00659bc03fec321ba8bce9420de607a1d37f8342eee1863174c69557/typing_extensions-4.12.2.tar.gz", hash = "sha256:1a7ead55c7e559dd4dee8856e3a88b41225abfe1ce8df57b7c13915fe121ffb8", size = 85321 }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/26/9f/ad63fc0248c5379346306f8668cda6e2e2e9c95e01216d2b8ffd9ff037d0/typing_extensions-4.12.2-py3-none-any.whl", hash = "sha256:04e5ca0351e0f3f85c6853954072df659d0d13fac324d0072316b67d7794700d", size = 37438 },
+]
+
 [[package]]
 name = "urllib3"
 version = "2.3.0"