diff --git a/snikket_web/prosodyclient.py b/snikket_web/prosodyclient.py
index bee17fe..57eac0c 100644
--- a/snikket_web/prosodyclient.py
+++ b/snikket_web/prosodyclient.py
@@ -359,7 +359,7 @@ class ProsodyClient:
         if app is not None:
             self.init_app(app)
 
-        self._client_info = None
+        self._client_info: typing.Optional[typing.Mapping[str, str]] = None
 
     @property
     def default_login_redirect(self) -> typing.Optional[str]:
@@ -418,13 +418,10 @@ class ProsodyClient:
             "scope", " ".join([SCOPE_RESTRICTED, SCOPE_DEFAULT, SCOPE_ADMIN])
         )
 
-        auth = BasicAuth(
-            login=self._client_info["client_id"],
-            password=self._client_info["client_secret"],
-        )
-
         self.logger.debug("sending OAuth2 request (payload omitted)")
-        async with session.post(self._login_endpoint, auth=auth, data=request) as resp:
+        async with session.post(
+            self._login_endpoint, auth=self.get_client_auth(), data=request
+        ) as resp:
             auth_status = resp.status
             auth_info: typing.Mapping[str, str] = await resp.json()
 
@@ -458,10 +455,10 @@ class ProsodyClient:
         http_session[self.SESSION_TOKEN] = token_info.token
         http_session[self.SESSION_CACHED_SCOPE] = " ".join(token_info.scopes)
 
-    def is_client_registered(self):
+    def is_client_registered(self) -> bool:
         return self._client_info is not None
 
-    async def register_client(self):
+    async def register_client(self) -> None:
         self.logger.debug(
             "sending OAuth2 client registration request (payload omitted)"
         )
@@ -493,6 +490,15 @@ class ProsodyClient:
 
                 self._client_info = await resp.json()
 
+    def get_client_auth(self) -> BasicAuth:
+        if self._client_info is None:
+            raise RuntimeError("Client is not registered")
+
+        return BasicAuth(
+            login=self._client_info["client_id"],
+            password=self._client_info["client_secret"],
+        )
+
     async def login(self, jid: str, password: str) -> bool:
         async with self._plain_session as session:
             token_info = await self._oauth2_bearer_token(