diff --git a/pyproject.toml b/pyproject.toml
index 0d8351860..d4047f41d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -125,7 +125,6 @@ ignore_errors = true
 module = [
     "quixstreams.core.*",
     "quixstreams.dataframe.*",
-    "quixstreams.platforms.*",
     "quixstreams.rowproducer.*"
 ]
 ignore_errors = true
diff --git a/quixstreams/models/topics/manager.py b/quixstreams/models/topics/manager.py
index 348134e37..47e014dc2 100644
--- a/quixstreams/models/topics/manager.py
+++ b/quixstreams/models/topics/manager.py
@@ -38,8 +38,8 @@ class TopicManager:
     """
 
     # Default topic params
-    default_num_partitions = 1
-    default_replication_factor = 1
+    default_num_partitions: Optional[int] = 1
+    default_replication_factor: Optional[int] = 1
     default_extra_config: dict[str, str] = {}
 
     # Max topic name length for the new topics
@@ -217,6 +217,9 @@ def _get_source_topic_config(
         if topic_config is None:
             raise RuntimeError(f"No configuration can be found for topic {topic_name}")
 
+        if topic_config is None:
+            raise RuntimeError(f"No configuration can be found for topic {topic_name}")
+
         # Copy only certain configuration values from original topic
         if extras_imports:
             topic_config.extra_config = {
diff --git a/quixstreams/models/topics/topic.py b/quixstreams/models/topics/topic.py
index 0a9d22589..d7b887d19 100644
--- a/quixstreams/models/topics/topic.py
+++ b/quixstreams/models/topics/topic.py
@@ -48,8 +48,8 @@ class TopicConfig:
     Generally used by Topic and any topic creation procedures.
     """
 
-    num_partitions: int
-    replication_factor: int
+    num_partitions: Optional[int]
+    replication_factor: Optional[int]
     extra_config: dict[str, str] = dataclasses.field(default_factory=dict)
 
     def as_dict(self):
diff --git a/quixstreams/platforms/quix/api.py b/quixstreams/platforms/quix/api.py
index f13ef3950..c48e3a5c3 100644
--- a/quixstreams/platforms/quix/api.py
+++ b/quixstreams/platforms/quix/api.py
@@ -32,7 +32,7 @@ class QuixPortalApiService:
 
     def __init__(
         self,
-        auth_token: Optional[str] = None,
+        auth_token: str,
         portal_api: Optional[str] = None,
         api_version: Optional[str] = None,
         default_workspace_id: Optional[str] = None,
@@ -40,12 +40,13 @@ def __init__(
         self._portal_api = (
             portal_api or QUIX_ENVIRONMENT.portal_api or DEFAULT_PORTAL_API_URL
         )
-        self._auth_token = auth_token or QUIX_ENVIRONMENT.sdk_token
-        if not self._auth_token:
+        if not auth_token:
             raise MissingConnectionRequirements(
                 f"A Quix Cloud auth token (SDK or PAT) is required; "
                 f"set with environment variable {QUIX_ENVIRONMENT.SDK_TOKEN}"
             )
+        self._auth_token = auth_token
+
         self._default_workspace_id = (
             default_workspace_id or QUIX_ENVIRONMENT.workspace_id
         )
@@ -133,7 +134,7 @@ def get_workspace_certificate(
             f"/workspaces/{workspace_id}/certificates", timeout=timeout
         ).content
         if not content:
-            return
+            return None
 
         with ZipFile(BytesIO(content)) as z:
             with z.open("ca.cert") as f:
diff --git a/quixstreams/platforms/quix/config.py b/quixstreams/platforms/quix/config.py
index 9c42ebdf9..1c7bfad3c 100644
--- a/quixstreams/platforms/quix/config.py
+++ b/quixstreams/platforms/quix/config.py
@@ -3,7 +3,7 @@
 import logging
 import time
 from copy import deepcopy
-from typing import List, Optional
+from typing import Any, List, Optional
 
 from requests import HTTPError
 
@@ -122,7 +122,7 @@ def __init__(
         try:
             self._workspace_id = workspace_id or self.api.default_workspace_id
         except UndefinedQuixWorkspaceId:
-            self._workspace_id = None
+            self._workspace_id = ""
             logger.warning(
                 "'workspace_id' argument was not provided nor set with "
                 "'Quix__Workspace__Id' environment; if only one Workspace ID for the "
@@ -130,9 +130,9 @@ def __init__(
                 "then that ID will be used. Otherwise, provide a known topic name to "
                 "method 'get_workspace_info(topic)' to obtain desired Workspace ID."
             )
-        self._librdkafka_connect_config = None
-        self._quix_broker_settings = None
-        self._workspace_meta = None
+        self._librdkafka_connect_config: Optional[ConnectionConfig] = None
+        self._quix_broker_settings: dict[str, Any] = {}
+        self._workspace_meta: dict[str, Any] = {}
         self._timeout = timeout
         self._topic_create_timeout = topic_create_timeout
 
@@ -175,18 +175,22 @@ def librdkafka_extra_config(self) -> dict:
         }
 
     @classmethod
-    def convert_topic_response(cls, api_response: dict) -> Topic:
+    def convert_topic_response(
+        cls, api_response: dict, extra_config: Optional[dict] = None
+    ) -> Topic:
         """
         Converts a GET or POST ("create") topic API response to a Topic object
 
         :param api_response: the dict response from a get or create topic call
         :return: a corresponding Topic object
         """
+        if extra_config is None:
+            extra_config = {}
+
         topic_config = api_response["configuration"]
-        extra_config = {
-            "retention.ms": topic_config["retentionInMinutes"] * 60 * 1000,
-            "retention.bytes": topic_config["retentionInBytes"],
-        }
+        extra_config["retention.ms"] = topic_config["retentionInMinutes"] * 60 * 1000
+        extra_config["retention.bytes"] = topic_config["retentionInBytes"]
+
         # Map value returned by Quix API to Kafka Admin API format
         if topic_config.get("cleanupPolicy"):
             cleanup_policy = _quix_cleanup_policy_to_kafka(
@@ -254,6 +258,7 @@ def search_for_workspace(
             for ws in ws_list:
                 if ws["name"] == workspace_name_or_id:
                     return ws
+            raise
 
     def _set_workspace_info(self, workspace_data: dict):
         ws_data = deepcopy(workspace_data)
@@ -280,14 +285,16 @@ def get_workspace_info(
         :param timeout: response timeout (seconds); Default 30
         """
         # TODO: more error handling with the wrong combo of ws_id and topic
+        ws_data: Optional[dict] = None
         if self._workspace_id:
             ws_data = self.search_for_workspace(
                 workspace_name_or_id=self._workspace_id, timeout=timeout
             )
-        else:
+        elif known_workspace_topic:
             ws_data = self.search_for_topic_workspace(
                 known_workspace_topic, timeout=timeout
             )
+
         if not ws_data:
             raise NoWorkspaceFound(
                 "No workspace was found for the given workspace/auth-token/topic combo"
@@ -316,6 +323,8 @@ def search_workspace_for_topic(
             if t["name"] == topic or t["id"] == topic:
                 return workspace_id
 
+        return None
+
     def search_for_topic_workspace(
         self, topic: str, timeout: Optional[float] = None
     ) -> Optional[dict]:
@@ -345,6 +354,8 @@ def search_for_topic_workspace(
             ):
                 return ws
 
+        return None
+
     def create_topic(self, topic: Topic, timeout: Optional[float] = None):
         """
         The actual API call to create the topic.
@@ -353,6 +364,8 @@ def create_topic(self, topic: Topic, timeout: Optional[float] = None):
         :param timeout: response timeout (seconds); Default 30
         """
         cfg = topic.config
+        if cfg is None:
+            raise RuntimeError("Topic config not set")
 
         # settings that must be ints or Nones
         ret_ms = cfg.extra_config.get("retention.ms")
@@ -366,7 +379,7 @@ def create_topic(self, topic: Topic, timeout: Optional[float] = None):
             topic_rep_factor=cfg.replication_factor,
             topic_ret_bytes=ret_bytes if ret_bytes is None else int(ret_bytes),
             topic_ret_minutes=ret_ms if ret_ms is None else int(ret_ms) // 60000,
-            cleanup_policy=cfg.extra_config.get("cleanup.policy"),
+            cleanup_policy=cfg.extra_config.get("cleanup.policy"),  # type: ignore[arg-type]
             timeout=timeout if timeout is not None else self._timeout,
         )
         logger.debug(
@@ -391,15 +404,17 @@ def get_or_create_topic(
         try:
             return self.get_topic(topic_name=topic.name, timeout=timeout)
         except QuixApiRequestFailure as e:
-            if e.status_code == 404:
-                # Topic likely does not exist (anything but success 404's; could inspect
-                # error string, but that creates a dependency on it never changing).
-                try:
-                    return self.create_topic(topic, timeout=timeout)
-                except QuixApiRequestFailure:
-                    # Multiple apps likely tried to create at the same time.
-                    # If this fails, it raises with all previous API errors
-                    return self.get_topic(topic_name=topic.name, timeout=timeout)
+            if e.status_code != 404:
+                raise
+
+            # Topic likely does not exist (anything but success 404's; could inspect
+            # error string, but that creates a dependency on it never changing).
+            try:
+                return self.create_topic(topic, timeout=timeout)
+            except QuixApiRequestFailure:
+                # Multiple apps likely tried to create at the same time.
+                # If this fails, it raises with all previous API errors
+                return self.get_topic(topic_name=topic.name, timeout=timeout)
 
     def wait_for_topic_ready_statuses(
         self,
diff --git a/quixstreams/platforms/quix/topic_manager.py b/quixstreams/platforms/quix/topic_manager.py
index 753a58685..1f3d76959 100644
--- a/quixstreams/platforms/quix/topic_manager.py
+++ b/quixstreams/platforms/quix/topic_manager.py
@@ -1,4 +1,4 @@
-from typing import List, Literal
+from typing import List, Literal, Optional
 
 from quixstreams.models.topics import Topic, TopicAdmin, TopicManager
 
@@ -22,8 +22,8 @@ class QuixTopicManager(TopicManager):
 
     # Default topic params
     # Set these to None to use defaults defined in Quix Cloud
-    default_num_partitions: None = None
-    default_replication_factor: None = None
+    default_num_partitions = None
+    default_replication_factor = None
 
     # Max topic name length for the new topics
     _max_topic_name_len = 249
@@ -54,7 +54,7 @@ def __init__(
             auto_create_topics=auto_create_topics,
         )
         self._quix_config_builder = quix_config_builder
-        self._topic_id_to_name = {}
+        self._topic_id_to_name: dict[str, str] = {}
 
     def _finalize_topic(self, topic: Topic) -> Topic:
         """
@@ -64,12 +64,11 @@ def _finalize_topic(self, topic: Topic) -> Topic:
         Additionally, sets the actual topic configuration since we now have it anyway.
         """
         quix_topic_info = self._quix_config_builder.get_or_create_topic(topic)
-        quix_topic = self._quix_config_builder.convert_topic_response(quix_topic_info)
-        # allows us to include the configs not included in the API response
-        quix_topic.config.extra_config = {
-            **topic.config.extra_config,
-            **quix_topic.config.extra_config,
-        }
+        quix_topic = self._quix_config_builder.convert_topic_response(
+            quix_topic_info,
+            extra_config=topic.config.extra_config if topic.config else {},
+        )
+
         topic_out = topic.__clone__(name=quix_topic.name, config=quix_topic.config)
         self._topic_id_to_name[topic_out.name] = quix_topic_info["name"]
         return super()._finalize_topic(topic_out)
@@ -86,7 +85,7 @@ def _create_topics(
     def _internal_name(
         self,
         topic_type: Literal["changelog", "repartition"],
-        topic_name: str,
+        topic_name: Optional[str],
         suffix: str,
     ):
         """
@@ -107,6 +106,6 @@ def _internal_name(
         """
         return super()._internal_name(
             topic_type,
-            self._topic_id_to_name[topic_name],
+            self._topic_id_to_name[topic_name] if topic_name else None,
             suffix,
         )
diff --git a/quixstreams/sources/core/kafka/kafka.py b/quixstreams/sources/core/kafka/kafka.py
index 398337b12..ed7b3d617 100644
--- a/quixstreams/sources/core/kafka/kafka.py
+++ b/quixstreams/sources/core/kafka/kafka.py
@@ -302,6 +302,13 @@ def _validate_topics(self) -> None:
             target_topic_config,
         )
 
+        # should never happen
+        if (
+            source_topic_config.num_partitions is None
+            or target_topic_config.num_partitions is None
+        ):
+            return
+
         if source_topic_config.num_partitions > target_topic_config.num_partitions:
             raise ValueError("Source topic has more partitions than destination topic")
         elif source_topic_config.num_partitions < target_topic_config.num_partitions:
diff --git a/tests/test_quixstreams/fixtures.py b/tests/test_quixstreams/fixtures.py
index d41550645..1cc941c31 100644
--- a/tests/test_quixstreams/fixtures.py
+++ b/tests/test_quixstreams/fixtures.py
@@ -378,8 +378,8 @@ def factory(workspace_id: Optional[str] = None):
             strip_workspace_id_prefix(workspace_id, s) if workspace_id else s
         )
 
-        cfg_builder.convert_topic_response.side_effect = (
-            lambda topic: QuixKafkaConfigsBuilder.convert_topic_response(topic)
+        cfg_builder.convert_topic_response = (
+            QuixKafkaConfigsBuilder.convert_topic_response
         )
 
         # Mock the create API call and return this response.