diff --git a/zerver/views/alert_words.py b/zerver/views/alert_words.py
index 684177abfc..dec5812642 100644
--- a/zerver/views/alert_words.py
+++ b/zerver/views/alert_words.py
@@ -11,12 +11,10 @@ from zerver.lib.validator import check_list, check_string
 from zerver.lib.actions import do_add_alert_words, do_remove_alert_words
 from zerver.lib.alert_words import user_alert_words
 
-def list_alert_words(request, user_profile):
-    # type: (HttpRequest, UserProfile) -> HttpResponse
+def list_alert_words(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
     return json_success({'alert_words': user_alert_words(user_profile)})
 
-def clean_alert_words(alert_words):
-    # type: (List[Text]) -> List[Text]
+def clean_alert_words(alert_words: List[Text]) -> List[Text]:
     alert_words = [w.strip() for w in alert_words]
     return [w for w in alert_words if w != ""]
 
diff --git a/zerver/views/compatibility.py b/zerver/views/compatibility.py
index 074d566e35..b2a22e1a6d 100644
--- a/zerver/views/compatibility.py
+++ b/zerver/views/compatibility.py
@@ -5,8 +5,7 @@ from typing import Any, List, Dict, Optional, Text
 from zerver.lib.response import json_error, json_success
 from zerver.lib.user_agent import parse_user_agent
 
-def check_compatibility(request):
-    # type: (HttpRequest) -> HttpResponse
+def check_compatibility(request: HttpRequest) -> HttpResponse:
     user_agent = parse_user_agent(request.META["HTTP_USER_AGENT"])
     if user_agent is None or user_agent['name'] == "ZulipInvalid":
         return json_error("Client is too old")
diff --git a/zerver/views/custom_profile_fields.py b/zerver/views/custom_profile_fields.py
index d6468d612c..9a89f1ec43 100644
--- a/zerver/views/custom_profile_fields.py
+++ b/zerver/views/custom_profile_fields.py
@@ -19,8 +19,7 @@ from zerver.lib.validator import check_dict, check_list, check_int
 from zerver.models import (custom_profile_fields_for_realm, UserProfile,
                            CustomProfileField, custom_profile_fields_for_realm)
 
-def list_realm_custom_profile_fields(request, user_profile):
-    # type: (HttpRequest, UserProfile) -> HttpResponse
+def list_realm_custom_profile_fields(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
     fields = custom_profile_fields_for_realm(user_profile.realm_id)
     return json_success({'custom_fields': [f.as_dict() for f in fields]})
 
@@ -46,8 +45,8 @@ def create_realm_custom_profile_field(request, user_profile, name=REQ(),
         return json_error(_("A field with that name already exists."))
 
 @require_realm_admin
-def delete_realm_custom_profile_field(request, user_profile, field_id):
-    # type: (HttpRequest, UserProfile, int) -> HttpResponse
+def delete_realm_custom_profile_field(request: HttpRequest, user_profile: UserProfile,
+                                      field_id: int) -> HttpResponse:
     try:
         field = CustomProfileField.objects.get(id=field_id)
     except CustomProfileField.DoesNotExist:
@@ -59,9 +58,8 @@ def delete_realm_custom_profile_field(request, user_profile, field_id):
 
 @require_realm_admin
 @has_request_variables
-def update_realm_custom_profile_field(request, user_profile, field_id,
-                                      name=REQ()):
-    # type: (HttpRequest, UserProfile, int, Text) -> HttpResponse
+def update_realm_custom_profile_field(request: HttpRequest, user_profile: UserProfile,
+                                      field_id: int, name: Text=REQ()) -> HttpResponse:
     if not name.strip():
         return json_error(_("Name cannot be blank."))
 
@@ -80,10 +78,10 @@ def update_realm_custom_profile_field(request, user_profile, field_id,
 @human_users_only
 @has_request_variables
 def update_user_custom_profile_data(
-        request,
-        user_profile,
-        data=REQ(validator=check_list(check_dict([('id', check_int)])))):
-    # type: (HttpRequest, UserProfile, List[Dict[str, Union[int, Text]]]) -> HttpResponse
+        request: HttpRequest,
+        user_profile: UserProfile,
+        data: List[Dict[str, Union[int, Text]]]=REQ(validator=check_list(
+            check_dict([('id', check_int)])))) -> HttpResponse:
     for item in data:
         field_id = item['id']
         try:
diff --git a/zerver/views/events_register.py b/zerver/views/events_register.py
index 816e756f78..b39927e8da 100644
--- a/zerver/views/events_register.py
+++ b/zerver/views/events_register.py
@@ -8,15 +8,15 @@ from zerver.lib.response import json_success
 from zerver.lib.validator import check_string, check_list, check_bool
 from zerver.models import Stream, UserProfile
 
-def _default_all_public_streams(user_profile, all_public_streams):
-    # type: (UserProfile, Optional[bool]) -> bool
+def _default_all_public_streams(user_profile: UserProfile,
+                                all_public_streams: Optional[bool]) -> bool:
     if all_public_streams is not None:
         return all_public_streams
     else:
         return user_profile.default_all_public_streams
 
-def _default_narrow(user_profile, narrow):
-    # type: (UserProfile, Iterable[Sequence[Text]]) -> Iterable[Sequence[Text]]
+def _default_narrow(user_profile: UserProfile,
+                    narrow: Iterable[Sequence[Text]]) -> Iterable[Sequence[Text]]:
     default_stream = user_profile.default_events_register_stream  # type: Optional[Stream]
     if not narrow and default_stream is not None:
         narrow = [['stream', default_stream.name]]
diff --git a/zerver/views/hotspots.py b/zerver/views/hotspots.py
index 0467e2fed3..c4bc191464 100644
--- a/zerver/views/hotspots.py
+++ b/zerver/views/hotspots.py
@@ -10,8 +10,8 @@ from zerver.models import UserProfile
 
 @human_users_only
 @has_request_variables
-def mark_hotspot_as_read(request, user, hotspot=REQ(validator=check_string)):
-    # type: (HttpRequest, UserProfile, str) -> HttpResponse
+def mark_hotspot_as_read(request: HttpRequest, user: UserProfile,
+                         hotspot: str=REQ(validator=check_string)) -> HttpResponse:
     if hotspot not in ALL_HOTSPOTS:
         return json_error(_('Unknown hotspot: %s') % (hotspot,))
     do_mark_hotspot_as_read(user, hotspot)
diff --git a/zerver/views/muting.py b/zerver/views/muting.py
index 02d48dc4cd..778d5738a3 100644
--- a/zerver/views/muting.py
+++ b/zerver/views/muting.py
@@ -14,8 +14,8 @@ from zerver.lib.streams import access_stream_by_name, access_stream_for_unmute_t
 from zerver.lib.validator import check_string, check_list
 from zerver.models import get_stream, Stream, UserProfile
 
-def mute_topic(user_profile, stream_name, topic_name):
-    # type: (UserProfile, str, str) -> HttpResponse
+def mute_topic(user_profile: UserProfile, stream_name: str,
+               topic_name: str) -> HttpResponse:
     (stream, recipient, sub) = access_stream_by_name(user_profile, stream_name)
 
     if topic_is_muted(user_profile, stream.id, topic_name):
@@ -24,8 +24,8 @@ def mute_topic(user_profile, stream_name, topic_name):
     do_mute_topic(user_profile, stream, recipient, topic_name)
     return json_success()
 
-def unmute_topic(user_profile, stream_name, topic_name):
-    # type: (UserProfile, str, str) -> HttpResponse
+def unmute_topic(user_profile: UserProfile, stream_name: str,
+                 topic_name: str) -> HttpResponse:
     error = _("Topic is not there in the muted_topics list")
     stream = access_stream_for_unmute_topic(user_profile, stream_name, error)
 
diff --git a/zerver/views/pointer.py b/zerver/views/pointer.py
index 99b3ab123d..c89067dd59 100644
--- a/zerver/views/pointer.py
+++ b/zerver/views/pointer.py
@@ -9,8 +9,7 @@ from zerver.lib.request import has_request_variables, JsonableError, REQ
 from zerver.lib.response import json_success
 from zerver.models import UserProfile, UserMessage
 
-def get_pointer_backend(request, user_profile):
-    # type: (HttpRequest, UserProfile) -> HttpResponse
+def get_pointer_backend(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
     return json_success({'pointer': user_profile.pointer})
 
 @has_request_variables
diff --git a/zerver/views/presence.py b/zerver/views/presence.py
index 51ba6f181b..87dcbb72b7 100644
--- a/zerver/views/presence.py
+++ b/zerver/views/presence.py
@@ -17,13 +17,12 @@ from zerver.lib.timestamp import datetime_to_timestamp
 from zerver.lib.validator import check_bool
 from zerver.models import UserActivity, UserPresence, UserProfile, get_user
 
-def get_status_list(requesting_user_profile):
-    # type: (UserProfile) -> Dict[str, Any]
+def get_status_list(requesting_user_profile: UserProfile) -> Dict[str, Any]:
     return {'presences': get_status_dict(requesting_user_profile),
             'server_timestamp': time.time()}
 
-def get_presence_backend(request, user_profile, email):
-    # type: (HttpRequest, UserProfile, Text) -> HttpResponse
+def get_presence_backend(request: HttpRequest, user_profile: UserProfile,
+                         email: Text) -> HttpResponse:
     try:
         target = get_user(email, user_profile.realm)
     except UserProfile.DoesNotExist:
diff --git a/zerver/views/push_notifications.py b/zerver/views/push_notifications.py
index 73458eb1dc..a6a0ca774d 100644
--- a/zerver/views/push_notifications.py
+++ b/zerver/views/push_notifications.py
@@ -16,8 +16,7 @@ from zerver.lib.response import json_success, json_error
 from zerver.lib.validator import check_string, check_list, check_bool
 from zerver.models import PushDeviceToken, UserProfile
 
-def validate_token(token_str, kind):
-    # type: (bytes, int) -> None
+def validate_token(token_str: bytes, kind: int) -> None:
     if token_str == '' or len(token_str) > 4096:
         raise JsonableError(_('Empty or invalid length token'))
     if kind == PushDeviceToken.APNS:
@@ -38,24 +37,24 @@ def add_apns_device_token(request, user_profile, token=REQ(),
 
 @human_users_only
 @has_request_variables
-def add_android_reg_id(request, user_profile, token=REQ()):
-    # type: (HttpRequest, UserProfile, bytes) -> HttpResponse
+def add_android_reg_id(request: HttpRequest, user_profile: UserProfile,
+                       token: bytes=REQ()) -> HttpResponse:
     validate_token(token, PushDeviceToken.GCM)
     add_push_device_token(user_profile, token, PushDeviceToken.GCM)
     return json_success()
 
 @human_users_only
 @has_request_variables
-def remove_apns_device_token(request, user_profile, token=REQ()):
-    # type: (HttpRequest, UserProfile, bytes) -> HttpResponse
+def remove_apns_device_token(request: HttpRequest, user_profile: UserProfile,
+                             token: bytes=REQ()) -> HttpResponse:
     validate_token(token, PushDeviceToken.APNS)
     remove_push_device_token(user_profile, token, PushDeviceToken.APNS)
     return json_success()
 
 @human_users_only
 @has_request_variables
-def remove_android_reg_id(request, user_profile, token=REQ()):
-    # type: (HttpRequest, UserProfile, bytes) -> HttpResponse
+def remove_android_reg_id(request: HttpRequest, user_profile: UserProfile,
+                          token: bytes=REQ()) -> HttpResponse:
     validate_token(token, PushDeviceToken.GCM)
     remove_push_device_token(user_profile, token, PushDeviceToken.GCM)
     return json_success()
diff --git a/zerver/views/realm_domains.py b/zerver/views/realm_domains.py
index a6713bc2e1..4d87464075 100644
--- a/zerver/views/realm_domains.py
+++ b/zerver/views/realm_domains.py
@@ -13,16 +13,15 @@ from zerver.models import RealmDomain, UserProfile, get_realm_domains
 
 from typing import Text
 
-def list_realm_domains(request, user_profile):
-    # type: (HttpRequest, UserProfile) -> (HttpResponse)
+def list_realm_domains(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
     domains = get_realm_domains(user_profile.realm)
     return json_success({'domains': domains})
 
 @require_realm_admin
 @has_request_variables
-def create_realm_domain(request, user_profile, domain=REQ(validator=check_string),
-                        allow_subdomains=REQ(validator=check_bool)):
-    # type: (HttpRequest, UserProfile, Text, bool) -> (HttpResponse)
+def create_realm_domain(request: HttpRequest, user_profile: UserProfile,
+                        domain: Text=REQ(validator=check_string),
+                        allow_subdomains: bool=REQ(validator=check_bool)) -> HttpResponse:
     domain = domain.strip().lower()
     try:
         validate_domain(domain)
@@ -35,9 +34,8 @@ def create_realm_domain(request, user_profile, domain=REQ(validator=check_string
 
 @require_realm_admin
 @has_request_variables
-def patch_realm_domain(request, user_profile, domain,
-                       allow_subdomains=REQ(validator=check_bool)):
-    # type: (HttpRequest, UserProfile, Text, bool) -> (HttpResponse)
+def patch_realm_domain(request: HttpRequest, user_profile: UserProfile, domain: Text,
+                       allow_subdomains: bool=REQ(validator=check_bool)) -> HttpResponse:
     try:
         realm_domain = RealmDomain.objects.get(realm=user_profile.realm, domain=domain)
         do_change_realm_domain(realm_domain, allow_subdomains)
@@ -47,8 +45,8 @@ def patch_realm_domain(request, user_profile, domain,
 
 @require_realm_admin
 @has_request_variables
-def delete_realm_domain(request, user_profile, domain):
-    # type: (HttpRequest, UserProfile, Text) -> (HttpResponse)
+def delete_realm_domain(request: HttpRequest, user_profile: UserProfile,
+                        domain: Text) -> HttpResponse:
     try:
         realm_domain = RealmDomain.objects.get(realm=user_profile.realm, domain=domain)
         do_remove_realm_domain(realm_domain)
diff --git a/zerver/views/realm_emoji.py b/zerver/views/realm_emoji.py
index 74ea1343b5..bd7ad8385f 100644
--- a/zerver/views/realm_emoji.py
+++ b/zerver/views/realm_emoji.py
@@ -14,8 +14,7 @@ from zerver.lib.response import json_success, json_error
 from zerver.lib.actions import check_add_realm_emoji, do_remove_realm_emoji
 
 
-def list_emoji(request, user_profile):
-    # type: (HttpRequest, UserProfile) -> HttpResponse
+def list_emoji(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
 
     # We don't call check_emoji_admin here because the list of realm
     # emoji is public.
@@ -23,8 +22,8 @@ def list_emoji(request, user_profile):
 
 
 @has_request_variables
-def upload_emoji(request, user_profile, emoji_name=REQ()):
-    # type: (HttpRequest, UserProfile, Text) -> HttpResponse
+def upload_emoji(request: HttpRequest, user_profile: UserProfile,
+                 emoji_name: Text=REQ()) -> HttpResponse:
     check_valid_emoji_name(emoji_name)
     check_emoji_admin(user_profile)
     if len(request.FILES) != 1:
@@ -42,8 +41,8 @@ def upload_emoji(request, user_profile, emoji_name=REQ()):
     return json_success()
 
 
-def delete_emoji(request, user_profile, emoji_name):
-    # type: (HttpRequest, UserProfile, Text) -> HttpResponse
+def delete_emoji(request: HttpRequest, user_profile: UserProfile,
+                 emoji_name: Text) -> HttpResponse:
     check_valid_emoji(user_profile.realm, emoji_name)
     check_emoji_admin(user_profile, emoji_name)
     do_remove_realm_emoji(user_profile.realm, emoji_name)
diff --git a/zerver/views/realm_filters.py b/zerver/views/realm_filters.py
index 679713256d..f13d8fef83 100644
--- a/zerver/views/realm_filters.py
+++ b/zerver/views/realm_filters.py
@@ -14,8 +14,7 @@ from zerver.models import realm_filters_for_realm, UserProfile, RealmFilter
 
 
 # Custom realm filters
-def list_filters(request, user_profile):
-    # type: (HttpRequest, UserProfile) -> HttpResponse
+def list_filters(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
     filters = realm_filters_for_realm(user_profile.realm_id)
     return json_success({'filters': filters})
 
@@ -37,8 +36,8 @@ def create_filter(request, user_profile, pattern=REQ(),
 
 
 @require_realm_admin
-def delete_filter(request, user_profile, filter_id):
-    # type: (HttpRequest, UserProfile, int) -> HttpResponse
+def delete_filter(request: HttpRequest, user_profile: UserProfile,
+                  filter_id: int) -> HttpResponse:
     try:
         do_remove_realm_filter(realm=user_profile.realm, id=filter_id)
     except RealmFilter.DoesNotExist:
diff --git a/zerver/views/realm_icon.py b/zerver/views/realm_icon.py
index a12f4c9c64..9c56703720 100644
--- a/zerver/views/realm_icon.py
+++ b/zerver/views/realm_icon.py
@@ -12,8 +12,7 @@ from zerver.models import UserProfile
 
 
 @require_realm_admin
-def upload_icon(request, user_profile):
-    # type: (HttpRequest, UserProfile) -> HttpResponse
+def upload_icon(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
 
     if len(request.FILES) != 1:
         return json_error(_("You must upload exactly one icon."))
@@ -33,8 +32,7 @@ def upload_icon(request, user_profile):
 
 
 @require_realm_admin
-def delete_icon_backend(request, user_profile):
-    # type: (HttpRequest, UserProfile) -> HttpResponse
+def delete_icon_backend(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
     # We don't actually delete the icon because it might still
     # be needed if the URL was cached and it is rewrited
     # in any case after next update.
@@ -46,8 +44,7 @@ def delete_icon_backend(request, user_profile):
     return json_success(json_result)
 
 
-def get_icon_backend(request, user_profile):
-    # type: (HttpRequest, UserProfile) -> HttpResponse
+def get_icon_backend(request: HttpRequest, user_profile: UserProfile) -> HttpResponse:
     url = realm_icon_url(user_profile.realm)
 
     # We can rely on the url already having query parameters. Because
diff --git a/zerver/views/report.py b/zerver/views/report.py
index fa74ec8287..849c784cbe 100644
--- a/zerver/views/report.py
+++ b/zerver/views/report.py
@@ -21,8 +21,7 @@ import os
 js_source_map = None
 
 # Read the source map information for decoding JavaScript backtraces.
-def get_js_source_map():
-    # type: () -> Optional[SourceMap]
+def get_js_source_map() -> Optional[SourceMap]:
     global js_source_map
     if not js_source_map and not (settings.DEVELOPMENT or settings.TEST_SUITE):
         js_source_map = SourceMap([
diff --git a/zerver/views/unsubscribe.py b/zerver/views/unsubscribe.py
index 6ec38f724b..c6050ec6fa 100644
--- a/zerver/views/unsubscribe.py
+++ b/zerver/views/unsubscribe.py
@@ -9,8 +9,8 @@ from zerver.lib.actions import do_change_notification_settings, clear_scheduled_
 from zerver.models import UserProfile, ScheduledEmail
 from zerver.context_processors import common_context
 
-def process_unsubscribe(request, token, subscription_type, unsubscribe_function):
-    # type: (HttpRequest, str, str, Callable[[UserProfile], None]) -> HttpResponse
+def process_unsubscribe(request: HttpRequest, token: str, subscription_type: str,
+                        unsubscribe_function: Callable[[UserProfile], None]) -> HttpResponse:
     try:
         confirmation = Confirmation.objects.get(confirmation_key=token)
     except Confirmation.DoesNotExist:
@@ -25,16 +25,13 @@ def process_unsubscribe(request, token, subscription_type, unsubscribe_function)
 # Email unsubscribe functions. All have the function signature
 # processor(user_profile).
 
-def do_missedmessage_unsubscribe(user_profile):
-    # type: (UserProfile) -> None
+def do_missedmessage_unsubscribe(user_profile: UserProfile) -> None:
     do_change_notification_settings(user_profile, 'enable_offline_email_notifications', False)
 
-def do_welcome_unsubscribe(user_profile):
-    # type: (UserProfile) -> None
+def do_welcome_unsubscribe(user_profile: UserProfile) -> None:
     clear_scheduled_emails(user_profile.id, ScheduledEmail.WELCOME)
 
-def do_digest_unsubscribe(user_profile):
-    # type: (UserProfile) -> None
+def do_digest_unsubscribe(user_profile: UserProfile) -> None:
     do_change_notification_settings(user_profile, 'enable_digest_emails', False)
 
 # The keys are part of the URL for the unsubscribe link and must be valid
@@ -48,8 +45,8 @@ email_unsubscribers = {
 }
 
 # Login NOT required. These are for one-click unsubscribes.
-def email_unsubscribe(request, email_type, confirmation_key):
-    # type: (HttpRequest, str, str) -> HttpResponse
+def email_unsubscribe(request: HttpRequest, email_type: str,
+                      confirmation_key: str) -> HttpResponse:
     if email_type in email_unsubscribers:
         display_name, unsubscribe_function = email_unsubscribers[email_type]
         return process_unsubscribe(request, confirmation_key, display_name, unsubscribe_function)