diff --git a/mautrix_telegram/formatter/__init__.py b/mautrix_telegram/formatter/__init__.py
index 6252455a..7cb102f7 100644
--- a/mautrix_telegram/formatter/__init__.py
+++ b/mautrix_telegram/formatter/__init__.py
@@ -1,8 +1,9 @@
 from .from_matrix import (matrix_reply_to_telegram, matrix_to_telegram, matrix_text_to_telegram,
                           init_mx)
 from .from_telegram import (telegram_reply_to_matrix, telegram_to_matrix, init_tg)
+from ..context import Context
 
 
-def init(context):
+def init(context: Context):
     init_mx(context)
     init_tg(context)
diff --git a/mautrix_telegram/formatter/from_matrix.py b/mautrix_telegram/formatter/from_matrix.py
index ffbc6878..aadc7b26 100644
--- a/mautrix_telegram/formatter/from_matrix.py
+++ b/mautrix_telegram/formatter/from_matrix.py
@@ -17,12 +17,18 @@
 from html import unescape
 from html.parser import HTMLParser
 from collections import deque
+from typing import Optional, List, Tuple, Type, Callable, Dict
 import math
 import re
 import logging
 
-from telethon_aio.tl.types import *
+from telethon_aio.tl.types import (TypeMessageEntity, MessageEntityMention,
+                                   InputMessageEntityMentionName, MessageEntityEmail,
+                                   MessageEntityUrl, MessageEntityTextUrl, MessageEntityBold,
+                                   MessageEntityItalic, MessageEntityCode, MessageEntityPre,
+                                   MessageEntityBotCommand, InputUser)
 
+from ..context import Context
 from .. import user as u, puppet as pu, portal as po
 from ..db import Message as DBMessage
 from .util import (add_surrogates, remove_surrogates, trim_reply_fallback_html,
@@ -51,7 +57,8 @@ class MatrixParser(HTMLParser):
         self._line_is_new = True
         self._list_entry_is_new = False
 
-    def _parse_url(self, url, args):
+    def _parse_url(self, url: str, args: Dict[str, str]
+                   ) -> Tuple[Optional[Type[TypeMessageEntity]], Optional[str]]:
         mention = self.mention_regex.match(url)
         if mention:
             mxid = mention.group(1)
@@ -80,7 +87,7 @@ class MatrixParser(HTMLParser):
             args["url"] = url
             return MessageEntityTextUrl, None
 
-    def handle_starttag(self, tag, attrs):
+    def handle_starttag(self, tag: str, attrs: List[Tuple[str, str]]):
         self._open_tags.appendleft(tag)
         self._open_tags_meta.appendleft(0)
 
@@ -127,7 +134,7 @@ class MatrixParser(HTMLParser):
             self._building_entities[tag] = entity_type(offset=offset, length=0, **args)
 
     @property
-    def _list_indent(self):
+    def _list_indent(self) -> int:
         indent = 0
         first_skipped = False
         for index, tag in enumerate(self._open_tags):
@@ -143,7 +150,7 @@ class MatrixParser(HTMLParser):
                 indent += 3
         return indent
 
-    def _newline(self, allow_multi=False):
+    def _newline(self, allow_multi: bool = False):
         if self._line_is_new and not allow_multi:
             return
         self.text += "\n"
@@ -151,7 +158,7 @@ class MatrixParser(HTMLParser):
         for entity in self._building_entities.values():
             entity.length += 1
 
-    def _handle_special_previous_tags(self, text):
+    def _handle_special_previous_tags(self, text: str) -> str:
         if "pre" not in self._open_tags and "code" not in self._open_tags:
             text = text.replace("\n", "")
         else:
@@ -166,7 +173,7 @@ class MatrixParser(HTMLParser):
             text = f"/{text}"
         return text
 
-    def _html_to_unicode(self, text):
+    def _html_to_unicode(self, text: str) -> str:
         strikethrough, underline = "del" in self._open_tags, "u" in self._open_tags
         if strikethrough and underline:
             text = html_to_unicode(text, "\u0336\u0332")
@@ -176,7 +183,7 @@ class MatrixParser(HTMLParser):
             text = html_to_unicode(text, "\u0332")
         return text
 
-    def _handle_tags_for_data(self, text):
+    def _handle_tags_for_data(self, text: str) -> Tuple[str, int]:
         extra_offset = 0
         list_entry_handled_once = False
         # In order to maintain order of things like blockquotes in lists or lists in blockquotes,
@@ -207,12 +214,12 @@ class MatrixParser(HTMLParser):
                 list_entry_handled_once = True
         return text, extra_offset
 
-    def _extend_entities_in_construction(self, text, extra_offset):
+    def _extend_entities_in_construction(self, text: str, extra_offset: int):
         for tag, entity in self._building_entities.items():
             entity.length += len(text) - extra_offset
             entity.offset += extra_offset
 
-    def handle_data(self, text):
+    def handle_data(self, text: str):
         text = unescape(text)
         text = self._handle_special_previous_tags(text)
         text = self._html_to_unicode(text)
@@ -221,7 +228,7 @@ class MatrixParser(HTMLParser):
         self._line_is_new = False
         self.text += text
 
-    def handle_endtag(self, tag):
+    def handle_endtag(self, tag: str):
         try:
             self._open_tags.popleft()
             self._open_tags_meta.popleft()
@@ -250,7 +257,7 @@ def plain_mention_to_html(match):
     return "".join(match.groups())
 
 
-def matrix_to_telegram(html):
+def matrix_to_telegram(html: str) -> Tuple[str, List[TypeMessageEntity]]:
     try:
         parser = MatrixParser()
         html = command_regex.sub(r"\1<command>\2</command>", html)
@@ -263,7 +270,8 @@ def matrix_to_telegram(html):
         log.exception("Failed to convert Matrix format:\nhtml=%s", html)
 
 
-def matrix_reply_to_telegram(content, tg_space, room_id=None):
+def matrix_reply_to_telegram(content: dict, tg_space: int, room_id: Optional[str] = None
+                             ) -> Optional[int]:
     try:
         reply = content["m.relates_to"]["m.in_reply_to"]
         room_id = room_id or reply["room_id"]
@@ -286,7 +294,7 @@ def matrix_reply_to_telegram(content, tg_space, room_id=None):
     return None
 
 
-def matrix_text_to_telegram(text):
+def matrix_text_to_telegram(text: str) -> Tuple[str, List[TypeMessageEntity]]:
     text = command_regex.sub(r"\1/\2", text)
     if should_bridge_plaintext_highlights:
         entities, pmr_replacer = plain_mention_to_text()
@@ -296,7 +304,7 @@ def matrix_text_to_telegram(text):
     return text, entities
 
 
-def plain_mention_to_text():
+def plain_mention_to_text() -> Tuple[List[TypeMessageEntity], Callable[[str], str]]:
     entities = []
 
     def replacer(match):
@@ -318,7 +326,7 @@ def plain_mention_to_text():
     return entities, replacer
 
 
-def init_mx(context):
+def init_mx(context: Context):
     global plain_mention_regex, should_bridge_plaintext_highlights
     config = context.config
     dn_template = config.get("bridge.displayname_template", "{displayname} (Telegram)")
diff --git a/mautrix_telegram/formatter/from_telegram.py b/mautrix_telegram/formatter/from_telegram.py
index 7a2bf442..2ec2d8f9 100644
--- a/mautrix_telegram/formatter/from_telegram.py
+++ b/mautrix_telegram/formatter/from_telegram.py
@@ -15,6 +15,8 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 from html import escape
+from typing import Optional, List, Tuple
+
 try:
     from lxml.html.diff import htmldiff
 except ImportError:
@@ -22,10 +24,16 @@ except ImportError:
 import logging
 import re
 
-from telethon_aio.tl.types import *
+from telethon_aio.tl.types import (MessageEntityMention, MessageEntityMentionName,
+                                   MessageEntityEmail, MessageEntityUrl, MessageEntityTextUrl,
+                                   MessageEntityBold, MessageEntityItalic, MessageEntityCode,
+                                   MessageEntityPre, MessageEntityBotCommand, Message, PeerChannel,
+                                   MessageEntityHashtag, TypeMessageEntity)
 from mautrix_appservice import MatrixRequestError
+from mautrix_appservice.intent_api import IntentAPI
 
 from .. import user as u, puppet as pu, portal as po
+from ..context import Context
 from ..db import Message as DBMessage
 from .util import (add_surrogates, remove_surrogates, trim_reply_fallback_html,
                    trim_reply_fallback_text, unicode_to_html)
@@ -34,7 +42,7 @@ log = logging.getLogger("mau.fmt.tg")
 should_highlight_edits = False
 
 
-def telegram_reply_to_matrix(evt, source):
+def telegram_reply_to_matrix(evt: Message, source: u.User) -> dict:
     if evt.reply_to_msg_id:
         space = (evt.to_id.channel_id
                  if isinstance(evt, Message) and isinstance(evt.to_id, PeerChannel)
@@ -50,7 +58,8 @@ def telegram_reply_to_matrix(evt, source):
     return {}
 
 
-async def _add_forward_header(source, text, html, fwd_from_id):
+async def _add_forward_header(source, text: str, html: Optional[str],
+                              fwd_from_id: Optional[int]) -> Tuple[str, str]:
     if not html:
         html = escape(text)
     user = u.User.get_by_tgid(fwd_from_id)
@@ -74,7 +83,7 @@ async def _add_forward_header(source, text, html, fwd_from_id):
     return text, html
 
 
-def highlight_edits(new_html, old_html):
+def highlight_edits(new_html: str, old_html: str) -> str:
     # Don't include `Edit:` text in diff.
     if old_html.startswith("<u>Edit:</u> "):
         old_html = old_html[len("<u>Edit:</u> "):]
@@ -89,7 +98,8 @@ def highlight_edits(new_html, old_html):
     return new_html
 
 
-async def _add_reply_header(source, text, html, evt, relates_to, main_intent, is_edit):
+async def _add_reply_header(source: u.User, text: str, html: str, evt: Message, relates_to: dict,
+                            main_intent: IntentAPI, is_edit: bool) -> Tuple[str, str]:
     space = (evt.to_id.channel_id
              if isinstance(evt, Message) and isinstance(evt.to_id, PeerChannel)
              else source.tgid)
@@ -145,8 +155,9 @@ async def _add_reply_header(source, text, html, evt, relates_to, main_intent, is
     return text_with_quote, html
 
 
-async def telegram_to_matrix(evt, source, main_intent=None, is_edit=False, prefix_text=None,
-                             prefix_html=None):
+async def telegram_to_matrix(evt: Message, source: u.User, main_intent: Optional[IntentAPI] = None,
+                             is_edit: bool = False, prefix_text: Optional[str] = None,
+                             prefix_html: Optional[str] = None) -> Tuple[str, str, dict]:
     text = add_surrogates(evt.message)
     html = _telegram_entities_to_matrix_catch(text, evt.entities) if evt.entities else None
     relates_to = {}
@@ -178,7 +189,7 @@ async def telegram_to_matrix(evt, source, main_intent=None, is_edit=False, prefi
     return remove_surrogates(text), remove_surrogates(html), relates_to
 
 
-def _telegram_entities_to_matrix_catch(text, entities):
+def _telegram_entities_to_matrix_catch(text: str, entities: List[TypeMessageEntity]) -> str:
     try:
         return _telegram_entities_to_matrix(text, entities)
     except Exception:
@@ -188,7 +199,7 @@ def _telegram_entities_to_matrix_catch(text, entities):
                       text, entities)
 
 
-def _telegram_entities_to_matrix(text, entities):
+def _telegram_entities_to_matrix(text: str, entities: List[TypeMessageEntity]) -> str:
     if not entities:
         return text
     html = []
@@ -232,7 +243,7 @@ def _telegram_entities_to_matrix(text, entities):
     return "".join(html)
 
 
-def _parse_pre(html, entity_text, language):
+def _parse_pre(html: List[str], entity_text: str, language: str) -> bool:
     if language:
         html.append("<pre>"
                     f"<code class='language-{language}'>{entity_text}</code>"
@@ -242,7 +253,7 @@ def _parse_pre(html, entity_text, language):
     return False
 
 
-def _parse_mention(html, entity_text):
+def _parse_mention(html: List[str], entity_text: str) -> bool:
     username = entity_text[1:]
 
     user = u.User.find_by_username(username) or pu.Puppet.find_by_username(username)
@@ -259,7 +270,7 @@ def _parse_mention(html, entity_text):
     return False
 
 
-def _parse_name_mention(html, entity_text, user_id):
+def _parse_name_mention(html: List[str], entity_text: str, user_id: int) -> bool:
     user = u.User.get_by_tgid(user_id)
     if user:
         mxid = user.mxid
@@ -273,7 +284,7 @@ def _parse_name_mention(html, entity_text, user_id):
     return False
 
 
-def _parse_url(html, entity_text, url):
+def _parse_url(html: List[str], entity_text: str, url: str) -> bool:
     url = escape(url) if url else entity_text
     if not url.startswith(("https://", "http://", "ftp://", "magnet://")):
         url = "http://" + url
@@ -281,6 +292,6 @@ def _parse_url(html, entity_text, url):
     return False
 
 
-def init_tg(context):
+def init_tg(context: Context):
     global should_highlight_edits
     should_highlight_edits = htmldiff and context.config["bridge.highlight_edits"]
diff --git a/mautrix_telegram/formatter/util.py b/mautrix_telegram/formatter/util.py
index a9806d53..f10146b4 100644
--- a/mautrix_telegram/formatter/util.py
+++ b/mautrix_telegram/formatter/util.py
@@ -15,6 +15,7 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 from html import escape
+from typing import Optional
 import struct
 import re
 
@@ -22,20 +23,20 @@ import re
 # add_surrogates and remove_surrogates are unicode surrogate utility functions from Telethon.
 # Licensed under the MIT license.
 # https://github.com/LonamiWebs/Telethon/blob/master/telethon/extensions/markdown.py
-def add_surrogates(text):
+def add_surrogates(text: Optional[str]) -> Optional[str]:
     if text is None:
         return None
     return "".join("".join(chr(y) for y in struct.unpack("<HH", x.encode("utf-16-le")))
                    if (0x10000 <= ord(x) <= 0x10FFFF) else x for x in text)
 
 
-def remove_surrogates(text):
+def remove_surrogates(text: Optional[str]) -> Optional[str]:
     if text is None:
         return None
     return text.encode("utf-16", "surrogatepass").decode("utf-16")
 
 
-def trim_reply_fallback_text(text):
+def trim_reply_fallback_text(text: str) -> str:
     if not text.startswith("> ") or "\n" not in text:
         return text
     lines = text.split("\n")
@@ -44,14 +45,14 @@ def trim_reply_fallback_text(text):
     return "\n".join(lines)
 
 
-HTML_REPLY_FALLBACK_REGEX = re.compile(r"^<blockquote data-mx-reply>[\s\S]+?</blockquote>")
+html_reply_fallback_regex = re.compile(r"^<blockquote data-mx-reply>[\s\S]+?</blockquote>")
 
 
-def trim_reply_fallback_html(html):
-    return HTML_REPLY_FALLBACK_REGEX.sub("", html)
+def trim_reply_fallback_html(html: str) -> str:
+    return html_reply_fallback_regex.sub("", html)
 
 
-def unicode_to_html(text, html, ctrl, tag):
+def unicode_to_html(text: str, html: str, ctrl: str, tag: str) -> str:
     if ctrl not in text:
         return html
     if not html:
@@ -79,5 +80,5 @@ def unicode_to_html(text, html, ctrl, tag):
     return html
 
 
-def html_to_unicode(text, ctrl):
+def html_to_unicode(text: str, ctrl: str) -> str:
     return ctrl.join(text) + ctrl