diff --git a/bemani/api/app.py b/bemani/api/app.py
index fd073bd..4d48d75 100644
--- a/bemani/api/app.py
+++ b/bemani/api/app.py
@@ -2,11 +2,12 @@ import copy
 import json
 import traceback
 from typing import Any, Callable, Dict
-from flask import Flask, abort, request, Response, g  # type: ignore
+from flask import Flask, abort, request, Response  # type: ignore
 from functools import wraps
 
 from bemani.api.exceptions import APIException
 from bemani.api.objects import RecordsObject, ProfileObject, StatisticsObject, CatalogObject
+from bemani.api.types import g
 from bemani.common import GameConstants, APIConstants, VersionConstants
 from bemani.data import Data
 
diff --git a/bemani/api/types.py b/bemani/api/types.py
new file mode 100644
index 0000000..93ff281
--- /dev/null
+++ b/bemani/api/types.py
@@ -0,0 +1,19 @@
+from typing import Any, Dict, TYPE_CHECKING
+
+
+if TYPE_CHECKING:
+    from flask.ctx import _AppCtxGlobals
+
+    from bemani.data import Data
+
+    class RequestGlobals(_AppCtxGlobals):
+        config: Dict[str, Any]
+        data: Data
+        authorized: bool
+
+    g = RequestGlobals()
+else:
+    from flask import g
+
+
+__all__ = ["g"]
diff --git a/bemani/data/mysql/machine.py b/bemani/data/mysql/machine.py
index 85803de..d9e6fef 100644
--- a/bemani/data/mysql/machine.py
+++ b/bemani/data/mysql/machine.py
@@ -288,7 +288,7 @@ class MachineData(BaseData):
         sql = "DELETE FROM `machine` WHERE pcbid = :pcbid LIMIT 1"
         self.execute(sql, {'pcbid': pcbid})
 
-    def create_arcade(self, name: str, description: str, data: Dict[str, Any], owners: List[int]) -> Arcade:
+    def create_arcade(self, name: str, description: str, data: Dict[str, Any], owners: List[UserID]) -> Arcade:
         """
         Given a set of values, create a new arcade and return the ID of that arcade.
 
diff --git a/bemani/frontend/account/account.py b/bemani/frontend/account/account.py
index 9ecea40..a4d1b48 100644
--- a/bemani/frontend/account/account.py
+++ b/bemani/frontend/account/account.py
@@ -1,10 +1,12 @@
 from typing import Dict, Any
-from flask import Blueprint, request, redirect, Response, url_for, make_response, render_template, g  # type: ignore
+from flask import Blueprint, request, redirect, Response, url_for, make_response, render_template
 
 from bemani.common import CardCipher, CardCipherException, AESCipher, Time
 from bemani.frontend.app import loginrequired, loginprohibited, success, error, jsonify, valid_email, valid_username, valid_pin, render_react
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
+
 
 account_pages = Blueprint(
     'account_pages',
diff --git a/bemani/frontend/admin/admin.py b/bemani/frontend/admin/admin.py
index c4af266..ef5b208 100644
--- a/bemani/frontend/admin/admin.py
+++ b/bemani/frontend/admin/admin.py
@@ -1,10 +1,10 @@
 import random
 from typing import Dict, Tuple, Any, Optional
-from flask import Blueprint, request, Response, render_template, url_for, g  # type: ignore
+from flask import Blueprint, request, Response, render_template, url_for
 
 from bemani.backend.base import Base
 from bemani.common import CardCipher, CardCipherException, GameConstants
-from bemani.data import Arcade, Machine, User, News, Event, Server, Client
+from bemani.data import Arcade, Machine, User, UserID, News, Event, Server, Client
 from bemani.data.api.client import APIClient, NotAuthorizedAPIException, APIException
 from bemani.frontend.app import adminrequired, jsonify, valid_email, valid_username, valid_pin, render_react
 from bemani.frontend.iidx.iidx import IIDXFrontend
@@ -12,6 +12,7 @@ from bemani.frontend.jubeat.jubeat import JubeatFrontend
 from bemani.frontend.popn.popn import PopnMusicFrontend
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
 
 admin_pages = Blueprint(
     'admin_pages',
@@ -52,7 +53,7 @@ def format_machine(machine: Machine) -> Dict[str, Any]:
     }
 
 
-def format_card(card: Tuple[str, Optional[int]]) -> Dict[str, Any]:
+def format_card(card: Tuple[str, Optional[UserID]]) -> Dict[str, Any]:
     owner = None
     if card[1] is not None:
         user = g.data.local.user.get_user(card[1])
@@ -316,6 +317,8 @@ def viewnews() -> Response:
 @admin_pages.route('/users/<int:userid>')
 @adminrequired
 def viewuser(userid: int) -> Response:
+    # Cast the userID.
+    userid = UserID(userid)
     user = g.data.local.user.get_user(userid)
 
     def __format_card(card: str) -> str:
@@ -356,6 +359,8 @@ def viewuser(userid: int) -> Response:
 @jsonify
 @adminrequired
 def listuser(userid: int) -> Dict[str, Any]:
+    # Cast the userID.
+    userid = UserID(userid)
 
     def __format_card(card: str) -> str:
         try:
@@ -788,9 +793,9 @@ def searchusers() -> Dict[str, Any]:
             actual_userid = g.data.local.user.from_cardid(cardid)
             if actual_userid is None:
                 # Force a non-match below
-                actual_userid = -1
+                actual_userid = UserID(-1)
         except CardCipherException:
-            actual_userid = -1
+            actual_userid = UserID(-1)
     else:
         actual_userid = None
 
@@ -809,6 +814,9 @@ def searchusers() -> Dict[str, Any]:
 @jsonify
 @adminrequired
 def updatebalance(userid: int) -> Dict[str, Any]:
+    # Cast the userID.
+    userid = UserID(userid)
+
     credits = request.get_json()['credits']
     user = g.data.local.user.get_user(userid)
     arcades = g.data.local.machine.get_all_arcades()
@@ -843,6 +851,9 @@ def updatebalance(userid: int) -> Dict[str, Any]:
 @jsonify
 @adminrequired
 def updateusername(userid: int) -> Dict[str, Any]:
+    # Cast the userID.
+    userid = UserID(userid)
+
     username = request.get_json()['username']
     user = g.data.local.user.get_user(userid)
     # Make sure the user ID is valid
@@ -870,6 +881,9 @@ def updateusername(userid: int) -> Dict[str, Any]:
 @jsonify
 @adminrequired
 def updateemail(userid: int) -> Dict[str, Any]:
+    # Cast the userID.
+    userid = UserID(userid)
+
     email = request.get_json()['email']
     user = g.data.local.user.get_user(userid)
     # Make sure the user ID is valid
@@ -892,6 +906,9 @@ def updateemail(userid: int) -> Dict[str, Any]:
 @jsonify
 @adminrequired
 def updatepin(userid: int) -> Dict[str, Any]:
+    # Cast the userID.
+    userid = UserID(userid)
+
     pin = request.get_json()['pin']
     user = g.data.local.user.get_user(userid)
     # Make sure the user ID is valid
@@ -911,6 +928,9 @@ def updatepin(userid: int) -> Dict[str, Any]:
 @jsonify
 @adminrequired
 def updatepassword(userid: int) -> Dict[str, Any]:
+    # Cast the userID.
+    userid = UserID(userid)
+
     new1 = request.get_json()['new1']
     new2 = request.get_json()['new2']
     user = g.data.local.user.get_user(userid)
@@ -936,6 +956,9 @@ def updatepassword(userid: int) -> Dict[str, Any]:
 @jsonify
 @adminrequired
 def removeusercard(userid: int) -> Dict[str, Any]:
+    # Cast the userID.
+    userid = UserID(userid)
+
     # Grab card, convert it
     card = request.get_json()['card']
     try:
@@ -960,6 +983,9 @@ def removeusercard(userid: int) -> Dict[str, Any]:
 @jsonify
 @adminrequired
 def addusercard(userid: int) -> Dict[str, Any]:
+    # Cast the userID.
+    userid = UserID(userid)
+
     # Grab card, convert it
     card = request.get_json()['card']
     try:
diff --git a/bemani/frontend/app.py b/bemani/frontend/app.py
index f7d8a42..0cccdb4 100644
--- a/bemani/frontend/app.py
+++ b/bemani/frontend/app.py
@@ -3,12 +3,13 @@ import re
 import traceback
 from typing import Callable, Dict, Any, Optional, List
 from react.jsx import JSXTransformer  # type: ignore
-from flask import Flask, flash, request, redirect, Response, url_for, render_template, got_request_exception, jsonify as flask_jsonify, g
+from flask import Flask, flash, request, redirect, Response, url_for, render_template, got_request_exception, jsonify as flask_jsonify
 from flask_caching import Cache  # type: ignore
 from functools import wraps
 
 from bemani.common import AESCipher, GameConstants
 from bemani.data import Data
+from bemani.frontend.types import g
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
 
diff --git a/bemani/frontend/arcade/arcade.py b/bemani/frontend/arcade/arcade.py
index 5f22907..afb19b6 100644
--- a/bemani/frontend/arcade/arcade.py
+++ b/bemani/frontend/arcade/arcade.py
@@ -1,12 +1,14 @@
 from typing import Any, Dict, List
-from flask import Blueprint, request, Response, abort, url_for, g  # type: ignore
+from flask import Blueprint, request, Response, abort, url_for
 
 from bemani.backend.base import Base
 from bemani.common import CardCipher, CardCipherException, ValidatedDict, GameConstants
-from bemani.data import Arcade, Event, Machine
+from bemani.data import Arcade, ArcadeID, Event, Machine
 from bemani.frontend.app import loginrequired, jsonify, render_react, valid_pin
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
+
 
 arcade_pages = Blueprint(
     'arcade_pages',
@@ -132,6 +134,9 @@ def get_game_settings(arcade: Arcade) -> List[Dict[str, Any]]:
 @arcade_pages.route('/<int:arcadeid>')
 @loginrequired
 def viewarcade(arcadeid: int) -> Response:
+    # Cast the ID for type safety.
+    arcadeid = ArcadeID(arcadeid)
+
     arcade = g.data.local.machine.get_arcade(arcadeid)
     if g.userID not in arcade.owners:
         abort(403)
@@ -168,6 +173,9 @@ def viewarcade(arcadeid: int) -> Response:
 @jsonify
 @loginrequired
 def listarcade(arcadeid: int) -> Dict[str, Any]:
+    # Cast the ID for type safety.
+    arcadeid = ArcadeID(arcadeid)
+
     # Make sure the arcade is valid
     arcade = g.data.local.machine.get_arcade(arcadeid)
     if arcade is None:
@@ -190,6 +198,8 @@ def listarcade(arcadeid: int) -> Dict[str, Any]:
 @jsonify
 @loginrequired
 def addbalance(arcadeid: int) -> Dict[str, Any]:
+    # Cast the ID for type safety.
+    arcadeid = ArcadeID(arcadeid)
     credits = request.get_json()['credits']
     card = request.get_json()['card']
 
@@ -234,6 +244,8 @@ def addbalance(arcadeid: int) -> Dict[str, Any]:
 @jsonify
 @loginrequired
 def updatebalance(arcadeid: int) -> Dict[str, Any]:
+    # Cast the ID for type safety.
+    arcadeid = ArcadeID(arcadeid)
     credits = request.get_json()['credits']
 
     # Make sure the arcade is valid
@@ -269,6 +281,9 @@ def updatebalance(arcadeid: int) -> Dict[str, Any]:
 @jsonify
 @loginrequired
 def updatepin(arcadeid: int) -> Dict[str, Any]:
+    # Cast the ID for type safety.
+    arcadeid = ArcadeID(arcadeid)
+
     pin = request.get_json()['pin']
 
     # Make sure the arcade is valid
@@ -293,6 +308,9 @@ def updatepin(arcadeid: int) -> Dict[str, Any]:
 @jsonify
 @loginrequired
 def updatearcade(arcadeid: int, attribute: str) -> Dict[str, Any]:
+    # Cast the ID for type safety.
+    arcadeid = ArcadeID(arcadeid)
+
     # Attempt to look this arcade up
     new_value = request.get_json()['value']
     arcade = g.data.local.machine.get_arcade(arcadeid)
@@ -322,6 +340,9 @@ def updatearcade(arcadeid: int, attribute: str) -> Dict[str, Any]:
 @jsonify
 @loginrequired
 def updatesettings(arcadeid: int) -> Dict[str, Any]:
+    # Cast the ID for type safety.
+    arcadeid = ArcadeID(arcadeid)
+
     # Attempt to look this arcade up
     arcade = g.data.local.machine.get_arcade(arcadeid)
 
diff --git a/bemani/frontend/bishi/endpoints.py b/bemani/frontend/bishi/endpoints.py
index afaaaf1..1c4c75b 100644
--- a/bemani/frontend/bishi/endpoints.py
+++ b/bemani/frontend/bishi/endpoints.py
@@ -1,7 +1,7 @@
 # vim: set fileencoding=utf-8
 import re
 from typing import Any, Dict
-from flask import Blueprint, request, Response, url_for, abort, g  # type: ignore
+from flask import Blueprint, request, Response, url_for, abort
 
 from bemani.common import GameConstants
 from bemani.data import UserID
@@ -9,6 +9,7 @@ from bemani.frontend.app import loginrequired, jsonify, render_react
 from bemani.frontend.bishi.bishi import BishiBashiFrontend
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
 
 
 bishi_pages = Blueprint(
diff --git a/bemani/frontend/ddr/endpoints.py b/bemani/frontend/ddr/endpoints.py
index 3c1675e..d7a0ba6 100644
--- a/bemani/frontend/ddr/endpoints.py
+++ b/bemani/frontend/ddr/endpoints.py
@@ -1,7 +1,7 @@
 # vim: set fileencoding=utf-8
 import re
 from typing import Any, Dict, List, Optional
-from flask import Blueprint, request, Response, url_for, abort, g  # type: ignore
+from flask import Blueprint, request, Response, url_for, abort
 
 from bemani.common import ID, GameConstants
 from bemani.data import Link, UserID
@@ -9,6 +9,8 @@ from bemani.frontend.app import loginrequired, jsonify, render_react
 from bemani.frontend.ddr.ddr import DDRFrontend
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
+
 
 ddr_pages = Blueprint(
     'ddr_pages',
diff --git a/bemani/frontend/home/home.py b/bemani/frontend/home/home.py
index 020180a..72574ea 100644
--- a/bemani/frontend/home/home.py
+++ b/bemani/frontend/home/home.py
@@ -1,10 +1,12 @@
-from flask import Blueprint, Response, g  # type: ignore
+from flask import Blueprint, Response
 from typing import Dict, Any
 
 from bemani.data import News
 from bemani.frontend.app import loginrequired, render_react
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
+
 
 home_pages = Blueprint(
     'home_pages',
diff --git a/bemani/frontend/iidx/endpoints.py b/bemani/frontend/iidx/endpoints.py
index 223cddf..a20a4bd 100644
--- a/bemani/frontend/iidx/endpoints.py
+++ b/bemani/frontend/iidx/endpoints.py
@@ -1,7 +1,7 @@
 # vim: set fileencoding=utf-8
 import re
 from typing import Any, Dict
-from flask import Blueprint, request, Response, url_for, abort, g  # type: ignore
+from flask import Blueprint, request, Response, url_for, abort
 
 from bemani.common import ID, GameConstants
 from bemani.data import UserID
@@ -9,6 +9,7 @@ from bemani.frontend.app import loginrequired, jsonify, render_react
 from bemani.frontend.iidx.iidx import IIDXFrontend
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
 
 iidx_pages = Blueprint(
     'iidx_pages',
diff --git a/bemani/frontend/jubeat/endpoints.py b/bemani/frontend/jubeat/endpoints.py
index 1e52e14..d7567f1 100644
--- a/bemani/frontend/jubeat/endpoints.py
+++ b/bemani/frontend/jubeat/endpoints.py
@@ -1,7 +1,7 @@
 # vim: set fileencoding=utf-8
 import re
 from typing import Any, Dict
-from flask import Blueprint, request, Response, url_for, abort, g  # type: ignore
+from flask import Blueprint, request, Response, url_for, abort
 
 from bemani.common import ID, GameConstants
 from bemani.data import UserID
@@ -9,6 +9,7 @@ from bemani.frontend.app import loginrequired, jsonify, render_react
 from bemani.frontend.jubeat.jubeat import JubeatFrontend
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
 
 jubeat_pages = Blueprint(
     'jubeat_pages',
diff --git a/bemani/frontend/museca/endpoints.py b/bemani/frontend/museca/endpoints.py
index 49d6cef..67fb39d 100644
--- a/bemani/frontend/museca/endpoints.py
+++ b/bemani/frontend/museca/endpoints.py
@@ -1,7 +1,7 @@
 # vim: set fileencoding=utf-8
 import re
 from typing import Any, Dict
-from flask import Blueprint, request, Response, url_for, abort, g  # type: ignore
+from flask import Blueprint, request, Response, url_for, abort
 
 from bemani.common import GameConstants
 from bemani.data import UserID
@@ -9,6 +9,8 @@ from bemani.frontend.app import loginrequired, jsonify, render_react
 from bemani.frontend.museca.museca import MusecaFrontend
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
+
 
 museca_pages = Blueprint(
     'museca_pages',
diff --git a/bemani/frontend/popn/endpoints.py b/bemani/frontend/popn/endpoints.py
index 03ab383..9d4e704 100644
--- a/bemani/frontend/popn/endpoints.py
+++ b/bemani/frontend/popn/endpoints.py
@@ -1,7 +1,7 @@
 # vim: set fileencoding=utf-8
 import re
 from typing import Any, Dict
-from flask import Blueprint, request, Response, url_for, abort, g  # type: ignore
+from flask import Blueprint, request, Response, url_for, abort
 
 from bemani.common import ID, GameConstants, VersionConstants
 from bemani.data import UserID
@@ -9,6 +9,8 @@ from bemani.frontend.app import loginrequired, jsonify, render_react
 from bemani.frontend.popn.popn import PopnMusicFrontend
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
+
 
 popn_pages = Blueprint(
     'popn_pages',
diff --git a/bemani/frontend/reflec/endpoints.py b/bemani/frontend/reflec/endpoints.py
index 32d72d4..30d282c 100644
--- a/bemani/frontend/reflec/endpoints.py
+++ b/bemani/frontend/reflec/endpoints.py
@@ -1,7 +1,7 @@
 # vim: set fileencoding=utf-8
 import re
 from typing import Any, Dict
-from flask import Blueprint, request, Response, url_for, abort, g  # type: ignore
+from flask import Blueprint, request, Response, url_for, abort
 
 from bemani.common import ID, GameConstants
 from bemani.data import UserID
@@ -9,6 +9,8 @@ from bemani.frontend.app import loginrequired, jsonify, render_react
 from bemani.frontend.reflec.reflec import ReflecBeatFrontend
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
+
 
 reflec_pages = Blueprint(
     'reflec_pages',
diff --git a/bemani/frontend/sdvx/endpoints.py b/bemani/frontend/sdvx/endpoints.py
index 35c7fe5..e576ba4 100644
--- a/bemani/frontend/sdvx/endpoints.py
+++ b/bemani/frontend/sdvx/endpoints.py
@@ -1,7 +1,7 @@
 # vim: set fileencoding=utf-8
 import re
 from typing import Any, Dict
-from flask import Blueprint, request, Response, url_for, abort, g  # type: ignore
+from flask import Blueprint, request, Response, url_for, abort
 
 from bemani.common import ID, GameConstants, VersionConstants
 from bemani.data import UserID
@@ -9,6 +9,8 @@ from bemani.frontend.app import loginrequired, jsonify, render_react
 from bemani.frontend.sdvx.sdvx import SoundVoltexFrontend
 from bemani.frontend.templates import templates_location
 from bemani.frontend.static import static_location
+from bemani.frontend.types import g
+
 
 sdvx_pages = Blueprint(
     'sdvx_pages',
diff --git a/bemani/frontend/types.py b/bemani/frontend/types.py
new file mode 100644
index 0000000..379a3e3
--- /dev/null
+++ b/bemani/frontend/types.py
@@ -0,0 +1,22 @@
+from typing import Any, Dict, Optional, TYPE_CHECKING
+
+
+if TYPE_CHECKING:
+    from flask.ctx import _AppCtxGlobals
+    from flask_caching import Cache  # type: ignore
+
+    from bemani.data import Data, UserID
+
+    class RequestGlobals(_AppCtxGlobals):
+        config: Dict[str, Any]
+        cache: Cache
+        data: Data
+        sessionID: Optional[str]
+        userID: Optional[UserID]
+
+    g = RequestGlobals()
+else:
+    from flask import g
+
+
+__all__ = ["g"]