diff --git a/MultiServer.py b/MultiServer.py
index 52c80c5540..ac3c9c18c1 100644
--- a/MultiServer.py
+++ b/MultiServer.py
@@ -43,8 +43,9 @@ import NetUtils
 import Utils
 from Utils import version_tuple, restricted_loads, Version, async_start, get_intended_text
 from NetUtils import Endpoint, ClientStatus, NetworkItem, decode, encode, NetworkPlayer, Permission, NetworkSlot, \
-    SlotType, LocationStore, MultiData, Hint, HintStatus
+    SlotType, LocationStore, MultiData, Hint, HintStatus, GamesPackage
 from BaseClasses import ItemClassification
+from apmw.multiserver.gamespackage.cache import GamesPackageCache
 
 
 min_client_version = Version(0, 5, 0)
@@ -240,21 +241,38 @@ class Context:
     slot_info: typing.Dict[int, NetworkSlot]
     generator_version = Version(0, 0, 0)
     checksums: typing.Dict[str, str]
+    played_games: set[str]
     item_names: typing.Dict[str, typing.Dict[int, str]]
-    item_name_groups: typing.Dict[str, typing.Dict[str, typing.Set[str]]]
+    item_name_groups: typing.Dict[str, typing.Dict[str, list[str]]]
     location_names: typing.Dict[str, typing.Dict[int, str]]
-    location_name_groups: typing.Dict[str, typing.Dict[str, typing.Set[str]]]
+    location_name_groups: typing.Dict[str, typing.Dict[str, list[str]]]
     all_item_and_group_names: typing.Dict[str, typing.Set[str]]
     all_location_and_group_names: typing.Dict[str, typing.Set[str]]
     non_hintable_names: typing.Dict[str, typing.AbstractSet[str]]
     spheres: typing.List[typing.Dict[int, typing.Set[int]]]
     """ each sphere is { player: { location_id, ... } } """
+    games_package_cache: GamesPackageCache
     logger: logging.Logger
 
-    def __init__(self, host: str, port: int, server_password: str, password: str, location_check_points: int,
-                 hint_cost: int, item_cheat: bool, release_mode: str = "disabled", collect_mode="disabled",
-                 countdown_mode: str = "auto", remaining_mode: str = "disabled", auto_shutdown: typing.SupportsFloat = 0, 
-                 compatibility: int = 2, log_network: bool = False, logger: logging.Logger = logging.getLogger()):
+    def __init__(
+            self,
+            host: str,
+            port: int,
+            server_password: str,
+            password: str,
+            location_check_points: int,
+            hint_cost: int,
+            item_cheat: bool,
+            release_mode: str = "disabled",
+            collect_mode="disabled",
+            countdown_mode: str = "auto",
+            remaining_mode: str = "disabled",
+            auto_shutdown: typing.SupportsFloat = 0,
+            compatibility: int = 2,
+            log_network: bool = False,
+            games_package_cache: GamesPackageCache | None = None,
+            logger: logging.Logger = logging.getLogger()
+    ) -> None:
         self.logger = logger
         super(Context, self).__init__()
         self.slot_info = {}
@@ -305,6 +323,7 @@ class Context:
         self.save_dirty = False
         self.tags = ['AP']
         self.games: typing.Dict[int, str] = {}
+        self.played_games = set()
         self.minimum_client_versions: typing.Dict[int, Version] = {}
         self.seed_name = ""
         self.groups = {}
@@ -314,9 +333,10 @@ class Context:
         self.stored_data_notification_clients = collections.defaultdict(weakref.WeakSet)
         self.read_data = {}
         self.spheres = []
+        self.games_package_cache = games_package_cache or GamesPackageCache()
 
         # init empty to satisfy linter, I suppose
-        self.gamespackage = {}
+        self.reduced_games_package = {}
         self.checksums = {}
         self.item_name_groups = {}
         self.location_name_groups = {}
@@ -328,50 +348,11 @@ class Context:
             lambda: Utils.KeyedDefaultDict(lambda code: f'Unknown location (ID:{code})'))
         self.non_hintable_names = collections.defaultdict(frozenset)
 
-        self._load_game_data()
-
-    # Data package retrieval
-    def _load_game_data(self):
-        import worlds
-        self.gamespackage = worlds.network_data_package["games"]
-
-        self.item_name_groups = {world_name: world.item_name_groups for world_name, world in
-                                 worlds.AutoWorldRegister.world_types.items()}
-        self.location_name_groups = {world_name: world.location_name_groups for world_name, world in
-                                     worlds.AutoWorldRegister.world_types.items()}
-        for world_name, world in worlds.AutoWorldRegister.world_types.items():
-            self.non_hintable_names[world_name] = world.hint_blacklist
-
-        for game_package in self.gamespackage.values():
-            # remove groups from data sent to clients
-            del game_package["item_name_groups"]
-            del game_package["location_name_groups"]
-
-    def _init_game_data(self):
-        for game_name, game_package in self.gamespackage.items():
-            if "checksum" in game_package:
-                self.checksums[game_name] = game_package["checksum"]
-            for item_name, item_id in game_package["item_name_to_id"].items():
-                self.item_names[game_name][item_id] = item_name
-            for location_name, location_id in game_package["location_name_to_id"].items():
-                self.location_names[game_name][location_id] = location_name
-            self.all_item_and_group_names[game_name] = \
-                set(game_package["item_name_to_id"]) | set(self.item_name_groups[game_name])
-            self.all_location_and_group_names[game_name] = \
-                set(game_package["location_name_to_id"]) | set(self.location_name_groups.get(game_name, []))
-
-        archipelago_item_names = self.item_names["Archipelago"]
-        archipelago_location_names = self.location_names["Archipelago"]
-        for game in [game_name for game_name in self.gamespackage if game_name != "Archipelago"]:
-            # Add Archipelago items and locations to each data package.
-            self.item_names[game].update(archipelago_item_names)
-            self.location_names[game].update(archipelago_location_names)
-
     def item_names_for_game(self, game: str) -> typing.Optional[typing.Dict[str, int]]:
-        return self.gamespackage[game]["item_name_to_id"] if game in self.gamespackage else None
+        return self.reduced_games_package[game]["item_name_to_id"] if game in self.reduced_games_package else None
 
     def location_names_for_game(self, game: str) -> typing.Optional[typing.Dict[str, int]]:
-        return self.gamespackage[game]["location_name_to_id"] if game in self.gamespackage else None
+        return self.reduced_games_package[game]["location_name_to_id"] if game in self.reduced_games_package else None
 
     # General networking
     async def send_msgs(self, endpoint: Endpoint, msgs: typing.Iterable[dict]) -> bool:
@@ -481,19 +462,17 @@ class Context:
             with open(multidatapath, 'rb') as f:
                 data = f.read()
 
-        self._load(self.decompress(data), {}, use_embedded_server_options)
+        self._load(self.decompress(data), use_embedded_server_options)
         self.data_filename = multidatapath
 
     @staticmethod
-    def decompress(data: bytes) -> dict:
+    def decompress(data: bytes) -> typing.Any:
         format_version = data[0]
         if format_version > 3:
             raise Utils.VersionException("Incompatible multidata.")
         return restricted_loads(zlib.decompress(data[1:]))
 
-    def _load(self, decoded_obj: MultiData, game_data_packages: typing.Dict[str, typing.Any],
-              use_embedded_server_options: bool):
-
+    def _load(self, decoded_obj: MultiData, use_embedded_server_options: bool) -> None:
         self.read_data = {}
         # there might be a better place to put this.
         self.read_data["race_mode"] = lambda: decoded_obj.get("race_mode", 0)
@@ -513,6 +492,7 @@ class Context:
 
         self.slot_info = decoded_obj["slot_info"]
         self.games = {slot: slot_info.game for slot, slot_info in self.slot_info.items()}
+        self.played_games = {"Archipelago"} | {self.games[x] for x in range(1, len(self.games) + 1)}
         self.groups = {slot: set(slot_info.group_members) for slot, slot_info in self.slot_info.items()
                        if slot_info.type == SlotType.group}
 
@@ -557,18 +537,11 @@ class Context:
             server_options = decoded_obj.get("server_options", {})
             self._set_options(server_options)
 
-        # embedded data package
-        for game_name, data in decoded_obj.get("datapackage", {}).items():
-            if game_name in game_data_packages:
-                data = game_data_packages[game_name]
-            self.logger.info(f"Loading embedded data package for game {game_name}")
-            self.gamespackage[game_name] = data
-            self.item_name_groups[game_name] = data["item_name_groups"]
-            if "location_name_groups" in data:
-                self.location_name_groups[game_name] = data["location_name_groups"]
-                del data["location_name_groups"]
-            del data["item_name_groups"]  # remove from data package, but keep in self.item_name_groups
+        # load and apply world data and (embedded) data package
+        self._load_world_data()
+        self._load_data_package(decoded_obj.get("datapackage", {}))
         self._init_game_data()
+
         for game_name, data in self.item_name_groups.items():
             self.read_data[f"item_name_groups_{game_name}"] = lambda lgame=game_name: self.item_name_groups[lgame]
         for game_name, data in self.location_name_groups.items():
@@ -577,6 +550,55 @@ class Context:
         # sorted access spheres
         self.spheres = decoded_obj.get("spheres", [])
 
+    def _load_world_data(self) -> None:
+        import worlds
+
+        for world_name, world in worlds.AutoWorldRegister.world_types.items():
+            # TODO: move hint_blacklist into GamesPackage?
+            self.non_hintable_names[world_name] = world.hint_blacklist
+
+    def _load_data_package(self, data_package: dict[str, GamesPackage]) -> None:
+        """Populates reduced_games_package, item_name_groups, location_name_groups from static data and data_package"""
+        # NOTE: for worlds loaded from db, only checksum is set in GamesPackage, but this is handled by cache
+        for game_name in sorted(self.played_games):
+            if game_name in data_package:
+                self.logger.info(f"Loading embedded data package for game {game_name}")
+                data = self.games_package_cache.get(game_name, data_package[game_name])
+            else:
+                # NOTE: we still allow uploading a game without datapackage. Once that is changed, we could drop this.
+                data = self.games_package_cache.get_static(game_name)
+            (
+                self.reduced_games_package[game_name],
+                self.item_name_groups[game_name],
+                self.location_name_groups[game_name],
+            ) = data
+
+        del self.games_package_cache  # Not used past this point. Free memory.
+
+    def _init_game_data(self) -> None:
+        """Update internal values from previously loaded data packages"""
+        for game_name, game_package in self.reduced_games_package.items():
+            if game_name not in self.played_games:
+                continue
+            if "checksum" in game_package:
+                self.checksums[game_name] = game_package["checksum"]
+            # NOTE: we could save more memory by moving the stuff below to data package cache as well
+            for item_name, item_id in game_package["item_name_to_id"].items():
+                self.item_names[game_name][item_id] = item_name
+            for location_name, location_id in game_package["location_name_to_id"].items():
+                self.location_names[game_name][location_id] = location_name
+            self.all_item_and_group_names[game_name] = \
+                set(game_package["item_name_to_id"]) | set(self.item_name_groups[game_name])
+            self.all_location_and_group_names[game_name] = \
+                set(game_package["location_name_to_id"]) | set(self.location_name_groups.get(game_name, []))
+
+        archipelago_item_names = self.item_names["Archipelago"]
+        archipelago_location_names = self.location_names["Archipelago"]
+        for game in [game_name for game_name in self.reduced_games_package if game_name != "Archipelago"]:
+            # Add Archipelago items and locations to each data package.
+            self.item_names[game].update(archipelago_item_names)
+            self.location_names[game].update(archipelago_location_names)
+
     # saving
 
     def save(self, now=False) -> bool:
@@ -917,12 +939,10 @@ async def server(websocket: "ServerConnection", path: str = "/", ctx: Context =
 
 
 async def on_client_connected(ctx: Context, client: Client):
-    games = {ctx.games[x] for x in range(1, len(ctx.games) + 1)}
-    games.add("Archipelago")
     await ctx.send_msgs(client, [{
         'cmd': 'RoomInfo',
         'password': bool(ctx.password),
-        'games': games,
+        'games': sorted(ctx.played_games),
         # tags are for additional features in the communication.
         # Name them by feature or fork, as you feel is appropriate.
         'tags': ctx.tags,
@@ -931,8 +951,7 @@ async def on_client_connected(ctx: Context, client: Client):
         'permissions': get_permissions(ctx),
         'hint_cost': ctx.hint_cost,
         'location_check_points': ctx.location_check_points,
-        'datapackage_checksums': {game: game_data["checksum"] for game, game_data
-                                  in ctx.gamespackage.items() if game in games and "checksum" in game_data},
+        'datapackage_checksums': ctx.checksums,
         'seed_name': ctx.seed_name,
         'time': time.time(),
     }])
@@ -1931,25 +1950,11 @@ async def process_client_cmd(ctx: Context, client: Client, args: dict):
             await ctx.send_msgs(client, reply)
 
     elif cmd == "GetDataPackage":
-        exclusions = args.get("exclusions", [])
-        if "games" in args:
-            games = {name: game_data for name, game_data in ctx.gamespackage.items()
-                     if name in set(args.get("games", []))}
-            await ctx.send_msgs(client, [{"cmd": "DataPackage",
-                                          "data": {"games": games}}])
-        # TODO: remove exclusions behaviour around 0.5.0
-        elif exclusions:
-            exclusions = set(exclusions)
-            games = {name: game_data for name, game_data in ctx.gamespackage.items()
-                     if name not in exclusions}
-
-            package = {"games": games}
-            await ctx.send_msgs(client, [{"cmd": "DataPackage",
-                                          "data": package}])
-
-        else:
-            await ctx.send_msgs(client, [{"cmd": "DataPackage",
-                                          "data": {"games": ctx.gamespackage}}])
+        games = {
+            name: game_data for name, game_data in ctx.reduced_games_package.items()
+            if name in set(args.get("games", []))
+        }
+        await ctx.send_msgs(client, [{"cmd": "DataPackage", "data": {"games": games}}])
 
     elif client.auth:
         if cmd == "ConnectUpdate":
diff --git a/WebHostLib/customserver.py b/WebHostLib/customserver.py
index e353cf2ab2..060afafd37 100644
--- a/WebHostLib/customserver.py
+++ b/WebHostLib/customserver.py
@@ -13,6 +13,7 @@ import threading
 import time
 import typing
 import sys
+from asyncio import AbstractEventLoop
 
 import websockets
 from pony.orm import commit, db_session, select
@@ -24,8 +25,10 @@ from MultiServer import (
     server_per_message_deflate_factory,
 )
 from Utils import restricted_loads, cache_argsless
+from NetUtils import GamesPackage
+from apmw.webhost.customserver.gamespackage.cache import DBGamesPackageCache
 from .locker import Locker
-from .models import Command, GameDataPackage, Room, db
+from .models import Command, Room, db
 
 
 class CustomClientMessageProcessor(ClientMessageProcessor):
@@ -62,18 +65,39 @@ class DBCommandProcessor(ServerCommandProcessor):
 
 class WebHostContext(Context):
     room_id: int
+    video: dict[tuple[int, int], tuple[str, str]]
+    main_loop: AbstractEventLoop
+    static_server_data: StaticServerData
 
-    def __init__(self, static_server_data: dict, logger: logging.Logger):
+    def __init__(
+            self,
+            static_server_data: StaticServerData,
+            games_package_cache: DBGamesPackageCache,
+            logger: logging.Logger,
+    ) -> None:
         # static server data is used during _load_game_data to load required data,
         # without needing to import worlds system, which takes quite a bit of memory
-        self.static_server_data = static_server_data
-        super(WebHostContext, self).__init__("", 0, "", "", 1,
-                                             40, True, "enabled", "enabled",
-                                             "enabled", 0, 2, logger=logger)
-        del self.static_server_data
-        self.main_loop = asyncio.get_running_loop()
-        self.video = {}
+        super(WebHostContext, self).__init__(
+            "",
+            0,
+            "",
+            "",
+            1,
+            40,
+            True,
+            "enabled",
+            "enabled",
+            "enabled",
+            0,
+            2,
+            games_package_cache=games_package_cache,
+            logger=logger,
+        )
         self.tags = ["AP", "WebHost"]
+        self.video = {}
+        self.main_loop = asyncio.get_running_loop()
+        self.static_server_data = static_server_data
+        self.games_package_cache = games_package_cache
 
     def __del__(self):
         try:
@@ -83,12 +107,6 @@ class WebHostContext(Context):
         except ImportError:
             self.logger.debug("Context destroyed")
 
-    def _load_game_data(self):
-        for key, value in self.static_server_data.items():
-            # NOTE: attributes are mutable and shared, so they will have to be copied before being modified
-            setattr(self, key, value)
-        self.non_hintable_names = collections.defaultdict(frozenset, self.non_hintable_names)
-
     async def listen_to_db_commands(self):
         cmdprocessor = DBCommandProcessor(self)
 
@@ -118,42 +136,14 @@ class WebHostContext(Context):
             self.port = get_random_port()
 
         multidata = self.decompress(room.seed.multidata)
-        game_data_packages = {}
+        return self._load(multidata, True)
 
-        static_gamespackage = self.gamespackage  # this is shared across all rooms
-        static_item_name_groups = self.item_name_groups
-        static_location_name_groups = self.location_name_groups
-        self.gamespackage = {"Archipelago": static_gamespackage.get("Archipelago", {})}  # this may be modified by _load
-        self.item_name_groups = {"Archipelago": static_item_name_groups.get("Archipelago", {})}
-        self.location_name_groups = {"Archipelago": static_location_name_groups.get("Archipelago", {})}
-        missing_checksum = False
-
-        for game in list(multidata.get("datapackage", {})):
-            game_data = multidata["datapackage"][game]
-            if "checksum" in game_data:
-                if static_gamespackage.get(game, {}).get("checksum") == game_data["checksum"]:
-                    # non-custom. remove from multidata and use static data
-                    # games package could be dropped from static data once all rooms embed data package
-                    del multidata["datapackage"][game]
-                else:
-                    row = GameDataPackage.get(checksum=game_data["checksum"])
-                    if row:  # None if rolled on >= 0.3.9 but uploaded to <= 0.3.8. multidata should be complete
-                        game_data_packages[game] = restricted_loads(row.data)
-                        continue
-                    else:
-                        self.logger.warning(f"Did not find game_data_package for {game}: {game_data['checksum']}")
-            else:
-                missing_checksum = True  # Game rolled on old AP and will load data package from multidata
-            self.gamespackage[game] = static_gamespackage.get(game, {})
-            self.item_name_groups[game] = static_item_name_groups.get(game, {})
-            self.location_name_groups[game] = static_location_name_groups.get(game, {})
-
-        if not game_data_packages and not missing_checksum:
-            # all static -> use the static dicts directly
-            self.gamespackage = static_gamespackage
-            self.item_name_groups = static_item_name_groups
-            self.location_name_groups = static_location_name_groups
-        return self._load(multidata, game_data_packages, True)
+    def _load_world_data(self):
+        # Use static_server_data, but skip static data package since that is in cache anyway.
+        # Also NOT importing worlds here!
+        # FIXME: does this copy the non_hintable_names (also for games not part of the room)?
+        self.non_hintable_names = collections.defaultdict(frozenset, self.static_server_data["non_hintable_names"])
+        del self.static_server_data  # Not used past this point. Free memory.
 
     def init_save(self, enabled: bool = True):
         self.saving = enabled
@@ -185,34 +175,23 @@ def get_random_port():
     return random.randint(49152, 65535)
 
 
+class StaticServerData(typing.TypedDict, total=True):
+    non_hintable_names: dict[str, typing.AbstractSet[str]]
+    games_package: dict[str, GamesPackage]
+
+
 @cache_argsless
-def get_static_server_data() -> dict:
+def get_static_server_data() -> StaticServerData:
     import worlds
-    data = {
+
+    return {
         "non_hintable_names": {
             world_name: world.hint_blacklist
             for world_name, world in worlds.AutoWorldRegister.world_types.items()
         },
-        "gamespackage": {
-            world_name: {
-                key: value
-                for key, value in game_package.items()
-                if key not in ("item_name_groups", "location_name_groups")
-            }
-            for world_name, game_package in worlds.network_data_package["games"].items()
-        },
-        "item_name_groups": {
-            world_name: world.item_name_groups
-            for world_name, world in worlds.AutoWorldRegister.world_types.items()
-        },
-        "location_name_groups": {
-            world_name: world.location_name_groups
-            for world_name, world in worlds.AutoWorldRegister.world_types.items()
-        },
+        "games_package": worlds.network_data_package["games"]
     }
 
-    return data
-
 
 def set_up_logging(room_id) -> logging.Logger:
     import os
@@ -245,9 +224,18 @@ def tear_down_logging(room_id):
         del logging.Logger.manager.loggerDict[logger_name]
 
 
-def run_server_process(name: str, ponyconfig: dict, static_server_data: dict,
-                       cert_file: typing.Optional[str], cert_key_file: typing.Optional[str],
-                       host: str, rooms_to_run: multiprocessing.Queue, rooms_shutting_down: multiprocessing.Queue):
+def run_server_process(
+        name: str,
+        ponyconfig: dict[str, typing.Any],
+        static_server_data: StaticServerData,
+        cert_file: typing.Optional[str],
+        cert_key_file: typing.Optional[str],
+        host: str,
+        rooms_to_run: multiprocessing.Queue,
+        rooms_shutting_down: multiprocessing.Queue
+) -> None:
+    import gc
+
     from setproctitle import setproctitle
 
     setproctitle(name)
@@ -263,6 +251,9 @@ def run_server_process(name: str, ponyconfig: dict, static_server_data: dict,
         resource.setrlimit(resource.RLIMIT_NOFILE, (file_limit, file_limit))
         del resource, file_limit
 
+    # prime the data package cache with static data
+    games_package_cache = DBGamesPackageCache(static_server_data["games_package"])
+
     # establish DB connection for multidata and multisave
     db.bind(**ponyconfig)
     db.generate_mapping(check_tables=False)
@@ -270,8 +261,6 @@ def run_server_process(name: str, ponyconfig: dict, static_server_data: dict,
     if "worlds" in sys.modules:
         raise Exception("Worlds system should not be loaded in the custom server.")
 
-    import gc
-
     if not cert_file:
         def get_ssl_context():
             return None
@@ -296,7 +285,7 @@ def run_server_process(name: str, ponyconfig: dict, static_server_data: dict,
         with Locker(f"RoomLocker {room_id}"):
             try:
                 logger = set_up_logging(room_id)
-                ctx = WebHostContext(static_server_data, logger)
+                ctx = WebHostContext(static_server_data, games_package_cache, logger)
                 ctx.load(room_id)
                 ctx.init_save()
                 assert ctx.server is None
diff --git a/apmw/__init__.py b/apmw/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/apmw/multiserver/__init__.py b/apmw/multiserver/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/apmw/multiserver/gamespackage/__init__.py b/apmw/multiserver/gamespackage/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/apmw/multiserver/gamespackage/cache.py b/apmw/multiserver/gamespackage/cache.py
new file mode 100644
index 0000000000..1a4dff9f81
--- /dev/null
+++ b/apmw/multiserver/gamespackage/cache.py
@@ -0,0 +1,110 @@
+import typing as t
+from weakref import WeakValueDictionary
+
+from NetUtils import GamesPackage, DataPackage
+
+GameAndChecksum = tuple[str, str | None]
+ItemNameGroups = dict[str, list[str]]
+LocationNameGroups = dict[str, list[str]]
+
+
+K = t.TypeVar("K")
+V = t.TypeVar("V")
+
+
+class DictLike(dict[K, V]):
+    __slots__ = ("__weakref__",)
+
+
+class GamesPackageCache:
+    # NOTE: this uses 3 separate collections because unpacking the get() result would end the container lifetime
+    _reduced_games_packages: WeakValueDictionary[GameAndChecksum, GamesPackage]
+    """Does not include item_name_groups nor location_name_groups"""
+    _item_name_groups: WeakValueDictionary[GameAndChecksum, dict[str, list[str]]]
+    _location_name_groups: WeakValueDictionary[GameAndChecksum, dict[str, list[str]]]
+
+    def __init__(self) -> None:
+        self._reduced_games_packages = WeakValueDictionary()
+        self._item_name_groups = WeakValueDictionary()
+        self._location_name_groups = WeakValueDictionary()
+
+    def _cached_item_name(self, key: GameAndChecksum, item_name: str) -> str:
+        """Returns a reference to an already-stored copy of item_name, or item_name"""
+        # TODO: there gotta be a better way, but maybe only in a C module?
+        for cached_item_name in self._reduced_games_packages[key].keys():
+            if cached_item_name == item_name:
+                return cached_item_name
+        return item_name
+
+    def _cached_location_name(self, key: GameAndChecksum, location_name: str) -> str:
+        """Returns a reference to an already-stored copy of location_name, or location_name"""
+        # TODO: as above
+        for cached_item_name in self._reduced_games_packages[key].keys():
+            if cached_item_name == location_name:
+                return cached_item_name
+        return location_name
+
+    def _get(
+        self,
+        cache_key: GameAndChecksum,
+    ) -> tuple[GamesPackage | None, ItemNameGroups | None, LocationNameGroups | None]:
+        if cache_key[1] is None:
+            return None, None, None
+        return (
+            self._reduced_games_packages.get(cache_key, None),
+            self._item_name_groups.get(cache_key, None),
+            self._location_name_groups.get(cache_key, None),
+        )
+
+    def get(
+        self,
+        game: str,
+        full_games_package: GamesPackage,
+    ) -> tuple[GamesPackage, ItemNameGroups, LocationNameGroups]:
+        """Loads and caches embedded data package provided by multidata"""
+        cache_key = (game, full_games_package.get("checksum", None))
+        cached_reduced_games_package, cached_item_name_groups, cached_location_name_groups = self._get(cache_key)
+
+        if cached_reduced_games_package is None:
+            cached_reduced_games_package = t.cast(
+                t.Any,
+                DictLike(
+                    {
+                        "item_name_to_id": full_games_package["item_name_to_id"],
+                        "location_name_to_id": full_games_package["location_name_to_id"],
+                        "checksum": full_games_package["checksum"],
+                    }
+                ),
+            )
+            if cache_key[1] is not None:  # only cache if checksum is available
+                self._reduced_games_packages[cache_key] = cached_reduced_games_package
+
+        if cached_item_name_groups is None:
+            cached_item_name_groups = DictLike(
+                {
+                    group_name: [self._cached_item_name(cache_key, item_name) for item_name in group_items]
+                    for group_name, group_items in full_games_package["item_name_groups"].items()
+                }
+            )
+            if cache_key[1] is not None:  # only cache if checksum is available
+                self._item_name_groups[cache_key] = cached_item_name_groups
+
+        if cached_location_name_groups is None:
+            cached_location_name_groups = DictLike(
+                {
+                    group_name: [
+                        self._cached_location_name(cache_key, location_name) for location_name in group_locations
+                    ]
+                    for group_name, group_locations in full_games_package.get("location_name_groups", {}).items()
+                }
+            )
+            if cache_key[1] is not None:  # only cache if checksum is available
+                self._location_name_groups[cache_key] = cached_location_name_groups
+
+        return cached_reduced_games_package, cached_item_name_groups, cached_location_name_groups
+
+    def get_static(self, game: str) -> tuple[GamesPackage, ItemNameGroups, LocationNameGroups]:
+        """Loads legacy data package from installed worlds"""
+        import worlds
+
+        return self.get(game, worlds.network_data_package["games"][game])
diff --git a/apmw/webhost/__init__.py b/apmw/webhost/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/apmw/webhost/customserver/__init__.py b/apmw/webhost/customserver/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/apmw/webhost/customserver/gamespackage/__init__.py b/apmw/webhost/customserver/gamespackage/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/apmw/webhost/customserver/gamespackage/cache.py b/apmw/webhost/customserver/gamespackage/cache.py
new file mode 100644
index 0000000000..8e3f7c83e0
--- /dev/null
+++ b/apmw/webhost/customserver/gamespackage/cache.py
@@ -0,0 +1,32 @@
+import typing as t
+
+from NetUtils import GamesPackage
+from Utils import restricted_loads
+from WebHostLib.models import GameDataPackage
+from apmw.multiserver.gamespackage.cache import GamesPackageCache, ItemNameGroups, LocationNameGroups
+
+
+class DBGamesPackageCache(GamesPackageCache):
+    _static: dict[str, tuple[GamesPackage, ItemNameGroups, LocationNameGroups]]
+
+    def __init__(self, static_games_package: dict[str, GamesPackage]) -> None:
+        super().__init__()
+        self._static = {game: super().get(game, games_package) for game, games_package in static_games_package.items()}
+
+    def get(
+        self,
+        game: str,
+        full_games_package: GamesPackage,
+    ) -> tuple[GamesPackage, ItemNameGroups, LocationNameGroups]:
+        # for games started on webhost, full_games_package is likely unpopulated and only has the checksum field
+        cache_key = (game, full_games_package.get("checksum", None))
+        cached = self._get(cache_key)
+        if any(value is None for value in cached):
+            row = GameDataPackage.get(checksum=full_games_package["checksum"])
+            if row:  # None if rolled on >= 0.3.9 but uploaded to <= 0.3.8 ...
+                return super().get(game, restricted_loads(row.data))
+            return super().get(game, full_games_package)  # ... in which case full_games_package should be populated
+        return t.cast(tuple[GamesPackage, ItemNameGroups, LocationNameGroups], cached)
+
+    def get_static(self, game: str) -> tuple[GamesPackage, ItemNameGroups, LocationNameGroups]:
+        return self._static[game]