diff --git a/api/.vscode/launch.json b/api/.vscode/launch.json
index 924c9c3..3fddcaa 100644
--- a/api/.vscode/launch.json
+++ b/api/.vscode/launch.json
@@ -21,7 +21,7 @@
         "${workspaceFolder}/advent22_api"
       ],
       "env": {
-        "ADVENT22__WEBDAV__CACHE_TTL": "30"
+        "ADVENT22__REDIS__CACHE_TTL": "30"
       },
       "justMyCode": true
     }
diff --git a/api/advent22_api/core/calendar_config.py b/api/advent22_api/core/calendar_config.py
index 8745232..0939d78 100644
--- a/api/advent22_api/core/calendar_config.py
+++ b/api/advent22_api/core/calendar_config.py
@@ -5,7 +5,7 @@ from fastapi import Depends
 from pydantic import BaseModel
 
 from .config import Config, get_config
-from .dav.webdav import WebDAV
+from .settings import WEBDAV
 
 
 class DoorSaved(BaseModel):
@@ -37,7 +37,7 @@ class CalendarConfig(BaseModel):
         Kalender Konfiguration ändern
         """
 
-        await WebDAV.write_str(
+        await WEBDAV.write_str(
             path=f"files/{cfg.calendar}",
             content=tomli_w.dumps(self.model_dump()),
         )
@@ -50,5 +50,5 @@ async def get_calendar_config(
     Kalender Konfiguration lesen
     """
 
-    txt = await WebDAV.read_str(path=f"files/{cfg.calendar}")
+    txt = await WEBDAV.read_str(path=f"files/{cfg.calendar}")
     return CalendarConfig.model_validate(tomllib.loads(txt))
diff --git a/api/advent22_api/core/config.py b/api/advent22_api/core/config.py
index 03c1730..f4c6b94 100644
--- a/api/advent22_api/core/config.py
+++ b/api/advent22_api/core/config.py
@@ -3,8 +3,7 @@ import tomllib
 from markdown import markdown
 from pydantic import BaseModel, ConfigDict, field_validator
 
-from .dav.webdav import WebDAV
-from .settings import SETTINGS, Credentials
+from .settings import SETTINGS, WEBDAV, Credentials
 from .transformed_string import TransformedString
 
 
@@ -77,5 +76,5 @@ async def get_config() -> Config:
     Globale Konfiguration lesen
     """
 
-    txt = await WebDAV.read_str(path=SETTINGS.webdav.config_filename)
+    txt = await WEBDAV.read_str(path=SETTINGS.webdav.config_filename)
     return Config.model_validate(tomllib.loads(txt))
diff --git a/api/advent22_api/core/dav/helpers.py b/api/advent22_api/core/dav/helpers.py
index e3e728a..c089003 100644
--- a/api/advent22_api/core/dav/helpers.py
+++ b/api/advent22_api/core/dav/helpers.py
@@ -1,8 +1,8 @@
+from itertools import chain
 from json import JSONDecodeError
-from typing import Callable, Hashable
+from typing import Any, Callable
 
 import requests
-from cachetools.keys import hashkey
 from CacheToolsUtils import RedisCache as __RedisCache
 from redis.typing import EncodableT, ResponseT
 from webdav3.client import Client as __WebDAVclient
@@ -11,12 +11,18 @@ from webdav3.client import Client as __WebDAVclient
 def davkey(
     name: str,
     slice: slice = slice(1, None),
-) -> Callable[..., tuple[Hashable, ...]]:
-    def func(*args, **kwargs) -> tuple[Hashable, ...]:
+) -> Callable[..., str]:
+    def func(*args: Any, **kwargs: Any) -> str:
         """Return a cache key for use with cached methods."""
 
-        key = hashkey(name, *args[slice], **kwargs)
-        return hashkey(*(str(key_item) for key_item in key))
+        call_args = chain(
+            # positional args
+            (f"{arg!r}" for arg in args[slice]),
+            # keyword args
+            (f"{k}:{v!r}" for k, v in kwargs.items()),
+        )
+
+        return f"{name}({', '.join(call_args)})"
 
     return func
 
diff --git a/api/advent22_api/core/dav/webdav.py b/api/advent22_api/core/dav/webdav.py
index a5d8b67..26125be 100644
--- a/api/advent22_api/core/dav/webdav.py
+++ b/api/advent22_api/core/dav/webdav.py
@@ -1,108 +1,113 @@
 import logging
 import re
+from dataclasses import dataclass
 from io import BytesIO
 
 from asyncify import asyncify
 from cachetools import cachedmethod
 from redis import Redis
 
-from ..settings import SETTINGS
 from .helpers import RedisCache, WebDAVclient, davkey
 
 _logger = logging.getLogger(__name__)
 
 
+@dataclass(kw_only=True, frozen=True, slots=True)
+class Settings:
+    url: str
+    username: str = "johndoe"
+    password: str = "s3cr3t!"
+
+
 class WebDAV:
-    _webdav_client = WebDAVclient(
-        {
-            "webdav_hostname": SETTINGS.webdav.url,
-            "webdav_login": SETTINGS.webdav.auth.username,
-            "webdav_password": SETTINGS.webdav.auth.password,
-        }
-    )
+    _webdav_client: WebDAVclient
+    _cache: RedisCache
 
-    _cache = RedisCache(
-        cache=Redis(
-            host=SETTINGS.redis.host,
-            port=SETTINGS.redis.port,
-            db=SETTINGS.redis.db,
-            protocol=SETTINGS.redis.protocol,
-        ),
-        ttl=SETTINGS.webdav.cache_ttl,
-    )
+    def __init__(self, settings: Settings, redis: Redis, ttl_sec: int) -> None:
+        try:
+            self._webdav_client = WebDAVclient(
+                {
+                    "webdav_hostname": settings.url,
+                    "webdav_login": settings.username,
+                    "webdav_password": settings.password,
+                }
+            )
+            assert self._webdav_client.check() is True
+
+        except AssertionError:
+            raise RuntimeError("WebDAV connection failed!")
+
+        self._cache = RedisCache(cache=redis, ttl=ttl_sec)
 
-    @classmethod
     @asyncify
-    @cachedmethod(cache=lambda cls: cls._cache, key=davkey("list_files"))
-    def list_files(
-        cls,
-        directory: str = "",
-        *,
-        regex: re.Pattern[str] = re.compile(""),
-    ) -> list[str]:
+    @cachedmethod(cache=lambda self: self._cache, key=davkey("list_files"))
+    def _list_files(self, directory: str = "") -> list[str]:
         """
         List files in directory `directory` matching RegEx `regex`
         """
 
-        _logger.debug(f"list_files {directory!r}")
-        ls = cls._webdav_client.list(directory)
+        return self._webdav_client.list(directory)
 
+    async def list_files(
+        self,
+        directory: str = "",
+        *,
+        regex: re.Pattern[str] = re.compile(""),
+    ) -> list[str]:
+        _logger.debug(f"list_files {directory!r} ({regex!r})")
+
+        ls = await self._list_files(directory)
         return [path for path in ls if regex.search(path)]
 
-    @classmethod
     @asyncify
-    @cachedmethod(cache=lambda cls: cls._cache, key=davkey("exists"))
-    def exists(cls, path: str) -> bool:
+    @cachedmethod(cache=lambda self: self._cache, key=davkey("exists"))
+    def exists(self, path: str) -> bool:
         """
         `True` iff there is a WebDAV resource at `path`
         """
 
         _logger.debug(f"file_exists {path!r}")
-        return cls._webdav_client.check(path)
+        return self._webdav_client.check(path)
 
-    @classmethod
     @asyncify
-    @cachedmethod(cache=lambda cls: cls._cache, key=davkey("read_bytes"))
-    def read_bytes(cls, path: str) -> bytes:
+    @cachedmethod(cache=lambda self: self._cache, key=davkey("read_bytes"))
+    def read_bytes(self, path: str) -> bytes:
         """
         Load WebDAV file from `path` as bytes
         """
 
         _logger.debug(f"read_bytes {path!r}")
         buffer = BytesIO()
-        cls._webdav_client.download_from(buffer, path)
+        self._webdav_client.download_from(buffer, path)
         buffer.seek(0)
 
         return buffer.read()
 
-    @classmethod
-    async def read_str(cls, path: str, encoding="utf-8") -> str:
+    async def read_str(self, path: str, encoding="utf-8") -> str:
         """
         Load WebDAV file from `path` as string
         """
 
         _logger.debug(f"read_str {path!r}")
-        return (await cls.read_bytes(path)).decode(encoding=encoding).strip()
+        return (await self.read_bytes(path)).decode(encoding=encoding).strip()
 
-    @classmethod
     @asyncify
-    def write_bytes(cls, path: str, buffer: bytes) -> None:
+    def write_bytes(self, path: str, buffer: bytes) -> None:
         """
         Write bytes from `buffer` into WebDAV file at `path`
         """
 
         _logger.debug(f"write_bytes {path!r}")
-        cls._webdav_client.upload_to(buffer, path)
+        self._webdav_client.upload_to(buffer, path)
 
         # invalidate cache entry
-        # explicit slice as there is no "cls" argument
-        del cls._cache[davkey("read_bytes", slice(0, None))(path)]
+        # begin slice at 0 (there is no "self" argument)
+        del self._cache[davkey("read_bytes", slice(0, None))(path)]
 
-    @classmethod
-    async def write_str(cls, path: str, content: str, encoding="utf-8") -> None:
+    async def write_str(self, path: str, content: str, encoding="utf-8") -> None:
         """
         Write string from `content` into WebDAV file at `path`
         """
 
         _logger.debug(f"write_str {path!r}")
-        await cls.write_bytes(path, content.encode(encoding=encoding))
+        await self.write_bytes(path, content.encode(encoding=encoding))
diff --git a/api/advent22_api/core/helpers.py b/api/advent22_api/core/helpers.py
index bbf7260..e9b6cd4 100644
--- a/api/advent22_api/core/helpers.py
+++ b/api/advent22_api/core/helpers.py
@@ -11,7 +11,7 @@ from PIL.Image import Image, Resampling
 from pydantic import BaseModel
 
 from .config import get_config
-from .dav.webdav import WebDAV
+from .settings import WEBDAV
 
 T = TypeVar("T")
 RE_IMG = re.compile(r"\.(gif|jpe?g|tiff?|png|bmp)$", flags=re.IGNORECASE)
@@ -94,7 +94,7 @@ def list_helper(
     async def _list_helper() -> list[str]:
         return [
             f"{directory}/{file}"
-            for file in await WebDAV.list_files(directory=directory, regex=regex)
+            for file in await WEBDAV.list_files(directory=directory, regex=regex)
         ]
 
     return _list_helper
@@ -110,10 +110,10 @@ async def load_image(file_name: str) -> Image:
     Versuche, Bild aus Datei zu laden
     """
 
-    if not await WebDAV.exists(file_name):
+    if not await WEBDAV.exists(file_name):
         raise RuntimeError(f"DAV-File {file_name} does not exist!")
 
-    return PILImage.open(BytesIO(await WebDAV.read_bytes(file_name)))
+    return PILImage.open(BytesIO(await WEBDAV.read_bytes(file_name)))
 
 
 class ImageData(BaseModel):
diff --git a/api/advent22_api/core/settings.py b/api/advent22_api/core/settings.py
index d4d9d39..c2e210b 100644
--- a/api/advent22_api/core/settings.py
+++ b/api/advent22_api/core/settings.py
@@ -1,5 +1,9 @@
 from pydantic import BaseModel, Field
 from pydantic_settings import BaseSettings, SettingsConfigDict
+from redis import ConnectionError, Redis
+
+from .dav.webdav import Settings as WebDAVSettings
+from .dav.webdav import WebDAV
 
 
 class Credentials(BaseModel):
@@ -22,7 +26,6 @@ class DavSettings(BaseModel):
         password="password",
     )
 
-    cache_ttl: int = 60 * 10
     config_filename: str = "config.toml"
 
     @property
@@ -39,10 +42,12 @@ class RedisSettings(BaseModel):
     Connection to a redis server.
     """
 
+    cache_ttl: int = 60 * 10
+
     host: str = "localhost"
     port: int = 6379
     db: int = 0
-    protocol: int = 3
+    protocol_version: int = 3
 
 
 class Settings(BaseSettings):
@@ -98,3 +103,26 @@ class Settings(BaseSettings):
 
 
 SETTINGS = Settings()
+
+try:
+    _REDIS = Redis(
+        host=SETTINGS.redis.host,
+        port=SETTINGS.redis.port,
+        db=SETTINGS.redis.db,
+        protocol=SETTINGS.redis.protocol_version,
+    )
+    _REDIS.ping()
+
+except ConnectionError:
+    raise RuntimeError("Redis connection failed!")
+
+
+WEBDAV = WebDAV(
+    WebDAVSettings(
+        url=SETTINGS.webdav.url,
+        username=SETTINGS.webdav.auth.username,
+        password=SETTINGS.webdav.auth.password,
+    ),
+    _REDIS,
+    SETTINGS.redis.cache_ttl,
+)
diff --git a/api/advent22_api/routers/admin.py b/api/advent22_api/routers/admin.py
index cc7fd8a..931d32e 100644
--- a/api/advent22_api/routers/admin.py
+++ b/api/advent22_api/routers/admin.py
@@ -59,7 +59,6 @@ class AdminConfigModel(BaseModel):
 
     class __WebDAV(BaseModel):
         url: str
-        cache_ttl: int
         config_file: str
 
     solution: __Solution
@@ -113,7 +112,7 @@ async def get_config_model(
             "redis": SETTINGS.redis,
             "webdav": {
                 "url": SETTINGS.webdav.url,
-                "cache_ttl": SETTINGS.webdav.cache_ttl,
+                "cache_ttl": SETTINGS.redis.cache_ttl,
                 "config_file": SETTINGS.webdav.config_filename,
             },
         }
diff --git a/ui/src/components/admin/ConfigView.vue b/ui/src/components/admin/ConfigView.vue
index 139095e..d0e5f7c 100644
--- a/ui/src/components/admin/ConfigView.vue
+++ b/ui/src/components/admin/ConfigView.vue
@@ -140,9 +140,6 @@
                 </BulmaSecret>
               </dd>
 
-              <dt>Cache-Dauer</dt>
-              <dd>{{ admin_config_model.webdav.cache_ttl }} s</dd>
-
               <dt>Konfigurationsdatei</dt>
               <dd>{{ admin_config_model.webdav.config_file }}</dd>
             </dl>
@@ -152,10 +149,11 @@
             <h3>Sonstige</h3>
             <dl>
               <dt>Redis</dt>
+              <dd>Cache-Dauer: {{ admin_config_model.redis.cache_ttl }} s</dd>
               <dd>Host: {{ admin_config_model.redis.host }}</dd>
               <dd>Port: {{ admin_config_model.redis.port }}</dd>
               <dd>Datenbank: {{ admin_config_model.redis.db }}</dd>
-              <dd>Protokoll: {{ admin_config_model.redis.protocol }}</dd>
+              <dd>Protokoll: {{ admin_config_model.redis.protocol_version }}</dd>
 
               <dt>UI-Admin</dt>
               <dd class="is-family-monospace">
@@ -219,14 +217,14 @@ const admin_config_model = ref<AdminConfigModel>({
   },
   fonts: [{ file: "consetetur", size: 0 }],
   redis: {
+    cache_ttl: 0,
     host: "0.0.0.0",
     port: 6379,
     db: 0,
-    protocol: 3,
+    protocol_version: 3,
   },
   webdav: {
     url: "sadipscing elitr",
-    cache_ttl: 0,
     config_file: "sed diam nonumy",
   },
 });
diff --git a/ui/src/lib/model.ts b/ui/src/lib/model.ts
index f2e021a..972e35d 100644
--- a/ui/src/lib/model.ts
+++ b/ui/src/lib/model.ts
@@ -26,14 +26,14 @@ export interface AdminConfigModel {
   };
   fonts: { file: string; size: number }[];
   redis: {
+    cache_ttl: number;
     host: string;
     port: number;
     db: number;
-    protocol: number;
+    protocol_version: number;
   };
   webdav: {
     url: string;
-    cache_ttl: number;
     config_file: string;
   };
 }