diff --git a/adafruit_io/adafruit_io.py b/adafruit_io/adafruit_io.py
index c667a28..dfafc14 100755
--- a/adafruit_io/adafruit_io.py
+++ b/adafruit_io/adafruit_io.py
@@ -22,6 +22,11 @@
 import json
 import re
 
+try:
+    from typing import List, Any, Callable, Optional
+except ImportError:
+    pass
+
 from adafruit_minimqtt.adafruit_minimqtt import MMQTTException
 from adafruit_io.adafruit_io_errors import (
     AdafruitIO_RequestError,
@@ -35,7 +40,7 @@
 CLIENT_HEADERS = {"User-Agent": "AIO-CircuitPython/{0}".format(__version__)}
 
 
-def validate_feed_key(feed_key):
+def validate_feed_key(feed_key: str):
     """Validates a provided feed key against Adafruit IO's system rules.
     https://learn.adafruit.com/naming-things-in-adafruit-io/the-two-feed-identifiers
     """
@@ -143,7 +148,7 @@ def _on_disconnect_mqtt(self, client, userdata, return_code):
             self.on_disconnect(self)
 
     # pylint: disable=not-callable
-    def _on_message_mqtt(self, client, topic, payload):
+    def _on_message_mqtt(self, client, topic: str, payload: str):
         """Runs when the client calls on_message. Parses and returns
         incoming data from Adafruit IO feeds.
 
@@ -195,7 +200,7 @@ def _on_unsubscribe_mqtt(self, client, user_data, topic, pid):
         if self.on_unsubscribe is not None:
             self.on_unsubscribe(self, user_data, topic, pid)
 
-    def add_feed_callback(self, feed_key, callback_method):
+    def add_feed_callback(self, feed_key: str, callback_method: Callable):
         """Attaches a callback_method to an Adafruit IO feed.
         The callback_method function is called when a
         new value is written to the feed.
@@ -211,7 +216,7 @@ def add_feed_callback(self, feed_key, callback_method):
             "{0}/f/{1}".format(self._user, feed_key), callback_method
         )
 
-    def remove_feed_callback(self, feed_key):
+    def remove_feed_callback(self, feed_key: str):
         """Removes a previously registered callback method
         from executing whenever feed_key receives new data.
 
@@ -239,7 +244,12 @@ def loop(self, timeout=1):
         self._client.loop(timeout)
 
     # Subscriptions
-    def subscribe(self, feed_key=None, group_key=None, shared_user=None):
+    def subscribe(
+        self,
+        feed_key: str = None,
+        group_key: str = None,
+        shared_user: Optional[str] = None,
+    ):
         """Subscribes to your Adafruit IO feed or group.
         Can also subscribe to someone else's feed.
 
@@ -277,7 +287,7 @@ def subscribe_to_errors(self):
         """
         self._client.subscribe("%s/errors" % self._user)
 
-    def subscribe_to_randomizer(self, randomizer_id):
+    def subscribe_to_randomizer(self, randomizer_id: int):
         """Subscribes to a random data stream created by the Adafruit IO Words service.
 
         :param int randomizer_id: Random word record you want data for.
@@ -286,7 +296,7 @@ def subscribe_to_randomizer(self, randomizer_id):
             "{0}/integration/words/{1}".format(self._user, randomizer_id)
         )
 
-    def subscribe_to_weather(self, weather_record, forecast):
+    def subscribe_to_weather(self, weather_record: int, forecast: str):
         """Subscribes to a weather forecast using the Adafruit IO PLUS weather
         service. This feature is only avaliable to Adafruit IO PLUS subscribers.
 
@@ -299,7 +309,7 @@ def subscribe_to_weather(self, weather_record, forecast):
             )
         )
 
-    def subscribe_to_time(self, time_type):
+    def subscribe_to_time(self, time_type: str):
         """Adafruit IO provides some built-in MQTT topics for getting the current server time.
 
         :param str time_type: Current Adafruit IO server time. Can be 'seconds', 'millis', or 'iso'.
@@ -312,7 +322,12 @@ def subscribe_to_time(self, time_type):
         else:
             self._client.subscribe("time/" + time_type)
 
-    def unsubscribe(self, feed_key=None, group_key=None, shared_user=None):
+    def unsubscribe(
+        self,
+        feed_key: str = None,
+        group_key: str = None,
+        shared_user: Optional[str] = None,
+    ):
         """Unsubscribes from an Adafruit IO feed or group.
         Can also subscribe to someone else's feed.
 
@@ -345,11 +360,13 @@ def unsubscribe(self, feed_key=None, group_key=None, shared_user=None):
             raise AdafruitIO_MQTTError("Must provide a feed_key or group_key.")
 
     # Publishing
-    def publish_multiple(self, feeds_and_data, timeout=3, is_group=False):
+    def publish_multiple(
+        self, feeds_and_data: List, timeout: int = 3, is_group: bool = False
+    ):
         """Publishes multiple data points to multiple feeds or groups with a variable
         timeout.
 
-        :param str feeds_and_data: List of tuples containing topic strings and data values.
+        :param list feeds_and_data: List of tuples containing topic strings and data values.
         :param int timeout: Delay between publishing data points to Adafruit IO, in seconds.
         :param bool is_group: Set to True if you're publishing to a group.
 
@@ -373,8 +390,15 @@ def publish_multiple(self, feeds_and_data, timeout=3, is_group=False):
             time.sleep(timeout)
 
     # pylint: disable=too-many-arguments
-    def publish(self, feed_key, data, metadata=None, shared_user=None, is_group=False):
-        """Publishes to an An Adafruit IO Feed.
+    def publish(
+        self,
+        feed_key: str,
+        data: str,
+        metadata: str = None,
+        shared_user: str = None,
+        is_group: bool = False,
+    ):
+        """Publishes to an Adafruit IO Feed.
 
         :param str feed_key: Adafruit IO Feed key.
         :param str data: Data to publish to the feed or group.
@@ -439,7 +463,7 @@ def publish(self, feed_key, data, metadata=None, shared_user=None, is_group=Fals
         else:
             self._client.publish("{0}/f/{1}".format(self._user, feed_key), data)
 
-    def get(self, feed_key):
+    def get(self, feed_key: str):
         """Calling this method will make Adafruit IO publish the most recent
         value on feed_key.
         https://io.adafruit.com/api/docs/mqtt.html#retained-values
@@ -484,7 +508,7 @@ def _create_headers(io_headers):
         return headers
 
     @staticmethod
-    def _create_data(data, metadata):
+    def _create_data(data, metadata: dict):
         """Returns a data payload as expected by the Adafruit IO HTTP API
 
         :param data: Payload value.
@@ -508,7 +532,7 @@ def _handle_error(response):
         if response.status_code >= 400:
             raise AdafruitIO_RequestError(response)
 
-    def _compose_path(self, path):
+    def _compose_path(self, path: str):
         """Composes a valid API request path.
 
         :param str path: Adafruit IO API URL path.
@@ -516,7 +540,7 @@ def _compose_path(self, path):
         return "https://io.adafruit.com/api/v2/{0}/{1}".format(self.username, path)
 
     # HTTP Requests
-    def _post(self, path, payload):
+    def _post(self, path: str, payload: Any):
         """
         POST data to Adafruit IO
 
@@ -531,7 +555,7 @@ def _post(self, path, payload):
 
         return json_data
 
-    def _get(self, path):
+    def _get(self, path: str):
         """
         GET data from Adafruit IO
 
@@ -544,7 +568,7 @@ def _get(self, path):
             json_data = response.json()
         return json_data
 
-    def _delete(self, path):
+    def _delete(self, path: str):
         """
         DELETE data from Adafruit IO.
 
@@ -559,7 +583,13 @@ def _delete(self, path):
         return json_data
 
     # Data
-    def send_data(self, feed_key, data, metadata=None, precision=None):
+    def send_data(
+        self,
+        feed_key: str,
+        data: str,
+        metadata: Optional[dict] = None,
+        precision: Optional[int] = None,
+    ):
         """
         Sends value data to a specified Adafruit IO feed.
 
@@ -580,7 +610,7 @@ def send_data(self, feed_key, data, metadata=None, precision=None):
         payload = self._create_data(data, metadata)
         self._post(path, payload)
 
-    def send_batch_data(self, feed_key, data_list):
+    def send_batch_data(self, feed_key: str, data_list: list):
         """
         Sends a batch array of data to a specified Adafruit IO feed
 
@@ -592,7 +622,7 @@ def send_batch_data(self, feed_key, data_list):
         data_dict = type(data_list)((data._asdict() for data in data_list))
         self._post(path, {"data": data_dict})
 
-    def receive_all_data(self, feed_key):
+    def receive_all_data(self, feed_key: str):
         """
         Get all data values from a specified Adafruit IO feed. Data is
         returned in reverse order.
@@ -603,7 +633,7 @@ def receive_all_data(self, feed_key):
         path = self._compose_path("feeds/{0}/data".format(feed_key))
         return self._get(path)
 
-    def receive_data(self, feed_key):
+    def receive_data(self, feed_key: str):
         """
         Return the most recent value for the specified feed.
 
@@ -613,7 +643,7 @@ def receive_data(self, feed_key):
         path = self._compose_path("feeds/{0}/data/last".format(feed_key))
         return self._get(path)
 
-    def delete_data(self, feed_key, data_id):
+    def delete_data(self, feed_key: str, data_id: str):
         """
         Deletes an existing Data point from a feed.
 
@@ -625,7 +655,7 @@ def delete_data(self, feed_key, data_id):
         return self._delete(path)
 
     # Groups
-    def create_new_group(self, group_key, group_description):
+    def create_new_group(self, group_key: str, group_description: str):
         """
         Creates a new Adafruit IO Group.
 
@@ -636,7 +666,7 @@ def create_new_group(self, group_key, group_description):
         payload = {"name": group_key, "description": group_description}
         return self._post(path, payload)
 
-    def delete_group(self, group_key):
+    def delete_group(self, group_key: str):
         """
         Deletes an existing group.
 
@@ -645,7 +675,7 @@ def delete_group(self, group_key):
         path = self._compose_path("groups/{0}".format(group_key))
         return self._delete(path)
 
-    def get_group(self, group_key):
+    def get_group(self, group_key: str):
         """
         Returns Group based on Group Key
 
@@ -654,7 +684,7 @@ def get_group(self, group_key):
         path = self._compose_path("groups/{0}".format(group_key))
         return self._get(path)
 
-    def create_feed_in_group(self, group_key, feed_name):
+    def create_feed_in_group(self, group_key: str, feed_name: str):
         """Creates a new feed in an existing group.
 
         :param str group_key: Group name.
@@ -664,7 +694,7 @@ def create_feed_in_group(self, group_key, feed_name):
         payload = {"feed": {"name": feed_name}}
         return self._post(path, payload)
 
-    def add_feed_to_group(self, group_key, feed_key):
+    def add_feed_to_group(self, group_key: str, feed_key: str):
         """
         Adds an existing feed to a group
 
@@ -677,7 +707,7 @@ def add_feed_to_group(self, group_key, feed_key):
         return self._post(path, payload)
 
     # Feeds
-    def get_feed(self, feed_key, detailed=False):
+    def get_feed(self, feed_key: str, detailed: bool = False):
         """
         Returns an Adafruit IO feed based on the feed key
 
@@ -691,7 +721,12 @@ def get_feed(self, feed_key, detailed=False):
             path = self._compose_path("feeds/{0}".format(feed_key))
         return self._get(path)
 
-    def create_new_feed(self, feed_key, feed_desc=None, feed_license=None):
+    def create_new_feed(
+        self,
+        feed_key: str,
+        feed_desc: Optional[str] = None,
+        feed_license: Optional[str] = None,
+    ):
         """
         Creates a new Adafruit IO feed.
 
@@ -705,7 +740,11 @@ def create_new_feed(self, feed_key, feed_desc=None, feed_license=None):
         return self._post(path, payload)
 
     def create_and_get_feed(
-        self, feed_key, detailed=False, feed_desc=None, feed_license=None
+        self,
+        feed_key: str,
+        detailed: bool = False,
+        feed_desc: Optional[str] = None,
+        feed_license: Optional[str] = None,
     ):
         """
         Attempts to return a feed; if the feed does not exist, it is created, and then returned.
@@ -723,7 +762,7 @@ def create_and_get_feed(
             )
             return self.get_feed(feed_key, detailed=detailed)
 
-    def delete_feed(self, feed_key):
+    def delete_feed(self, feed_key: str):
         """
         Deletes an existing feed.
 
@@ -734,7 +773,7 @@ def delete_feed(self, feed_key):
         return self._delete(path)
 
     # Adafruit IO Connected Services
-    def receive_weather(self, weather_id):
+    def receive_weather(self, weather_id: int):
         """
         Get data from the Adafruit IO Weather Forecast Service
         NOTE: This service is avaliable to Adafruit IO Plus subscribers only.
@@ -744,7 +783,7 @@ def receive_weather(self, weather_id):
         path = self._compose_path("integrations/weather/{0}".format(weather_id))
         return self._get(path)
 
-    def receive_random_data(self, generator_id):
+    def receive_random_data(self, generator_id: int):
         """
         Get data from the Adafruit IO Random Data Stream Service