diff --git a/backend/alembic/__init__.py b/backend/alembic/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/backend/onyx/auth/users.py b/backend/onyx/auth/users.py
index 0d8fa54745..da9865550f 100644
--- a/backend/onyx/auth/users.py
+++ b/backend/onyx/auth/users.py
@@ -245,6 +245,8 @@ class UserManager(UUIDIDMixin, BaseUserManager[User, uuid.UUID]):
             referral_source=referral_source,
             request=request,
         )
+        user: User
+
         async with get_async_session_with_tenant(tenant_id) as db_session:
             token = CURRENT_TENANT_ID_CONTEXTVAR.set(tenant_id)
             verify_email_is_invited(user_create.email)
@@ -368,6 +370,8 @@ class UserManager(UUIDIDMixin, BaseUserManager[User, uuid.UUID]):
                 "refresh_token": refresh_token,
             }
 
+            user: User
+
             try:
                 # Attempt to get user by OAuth account
                 user = await self.get_by_oauth_account(oauth_name, account_id)
diff --git a/backend/onyx/background/celery/tasks/indexing/tasks.py b/backend/onyx/background/celery/tasks/indexing/tasks.py
index 2e3c0e3aec..b1451a0512 100644
--- a/backend/onyx/background/celery/tasks/indexing/tasks.py
+++ b/backend/onyx/background/celery/tasks/indexing/tasks.py
@@ -586,11 +586,12 @@ def connector_indexing_proxy_task(
 
         # if the job is done, clean up and break
         if job.done():
+            exit_code: int | None
             try:
                 if job.status == "error":
                     ignore_exitcode = False
 
-                    exit_code: int | None = None
+                    exit_code = None
                     if job.process:
                         exit_code = job.process.exitcode
 
diff --git a/backend/onyx/background/celery/tasks/indexing/utils.py b/backend/onyx/background/celery/tasks/indexing/utils.py
index e14e79b5ff..00cbc3632d 100644
--- a/backend/onyx/background/celery/tasks/indexing/utils.py
+++ b/backend/onyx/background/celery/tasks/indexing/utils.py
@@ -438,6 +438,7 @@ def try_creating_indexing_task(
     if not acquired:
         return None
 
+    redis_connector_index: RedisConnectorIndex
     try:
         redis_connector = RedisConnector(tenant_id, cc_pair.id)
         redis_connector_index = redis_connector.new_index(search_settings.id)
diff --git a/backend/onyx/background/celery/tasks/monitoring/tasks.py b/backend/onyx/background/celery/tasks/monitoring/tasks.py
index 0375608413..244b4abd2e 100644
--- a/backend/onyx/background/celery/tasks/monitoring/tasks.py
+++ b/backend/onyx/background/celery/tasks/monitoring/tasks.py
@@ -747,6 +747,7 @@ def cloud_check_alembic() -> bool | None:
     revision_counts: dict[str, int] = {}
     out_of_date_tenants: dict[str, str | None] = {}
     top_revision: str = ""
+    tenant_ids: list[str] = []
 
     try:
         # map each tenant_id to its revision
diff --git a/backend/onyx/background/celery/tasks/shared/tasks.py b/backend/onyx/background/celery/tasks/shared/tasks.py
index 5530d9eebc..a1bc12252a 100644
--- a/backend/onyx/background/celery/tasks/shared/tasks.py
+++ b/backend/onyx/background/celery/tasks/shared/tasks.py
@@ -247,6 +247,7 @@ def cloud_beat_task_generator(
         return None
 
     last_lock_time = time.monotonic()
+    tenant_ids: list[str] | list[None] = []
 
     try:
         tenant_ids = get_all_tenant_ids()
diff --git a/backend/onyx/background/celery/tasks/vespa/tasks.py b/backend/onyx/background/celery/tasks/vespa/tasks.py
index c695f92a8b..4033b2503f 100644
--- a/backend/onyx/background/celery/tasks/vespa/tasks.py
+++ b/backend/onyx/background/celery/tasks/vespa/tasks.py
@@ -1084,6 +1084,7 @@ def vespa_metadata_sync_task(
         task_logger.info(f"SoftTimeLimitExceeded exception. doc={document_id}")
         return False
     except Exception as ex:
+        e: Exception | None = None
         if isinstance(ex, RetryError):
             task_logger.warning(
                 f"Tenacity retry failed: num_attempts={ex.last_attempt.attempt_number}"
diff --git a/backend/onyx/background/indexing/run_indexing.py b/backend/onyx/background/indexing/run_indexing.py
index 94f8cb01be..fd0ab0b35d 100644
--- a/backend/onyx/background/indexing/run_indexing.py
+++ b/backend/onyx/background/indexing/run_indexing.py
@@ -239,6 +239,7 @@ def _run_indexing(
         callback=callback,
     )
 
+    tracer: OnyxTracer
     if INDEXING_TRACER_INTERVAL > 0:
         logger.debug(f"Memory tracer starting: interval={INDEXING_TRACER_INTERVAL}")
         tracer = OnyxTracer()
diff --git a/backend/onyx/chat/process_message.py b/backend/onyx/chat/process_message.py
index 8c1de70ca9..f87de5f488 100644
--- a/backend/onyx/chat/process_message.py
+++ b/backend/onyx/chat/process_message.py
@@ -87,6 +87,7 @@ from onyx.file_store.utils import save_files
 from onyx.llm.exceptions import GenAIDisabledException
 from onyx.llm.factory import get_llms_for_persona
 from onyx.llm.factory import get_main_llm_from_tuple
+from onyx.llm.interfaces import LLM
 from onyx.llm.models import PreviousMessage
 from onyx.llm.utils import litellm_exception_to_error_msg
 from onyx.natural_language_processing.utils import get_tokenizer
@@ -349,7 +350,8 @@ def stream_chat_message_objects(
     new_msg_req.chunks_above = 0
     new_msg_req.chunks_below = 0
 
-    llm = None
+    llm: LLM
+
     try:
         user_id = user.id if user is not None else None
 
diff --git a/backend/onyx/connectors/airtable/airtable_connector.py b/backend/onyx/connectors/airtable/airtable_connector.py
index 37b84623f9..c4d0e63d90 100644
--- a/backend/onyx/connectors/airtable/airtable_connector.py
+++ b/backend/onyx/connectors/airtable/airtable_connector.py
@@ -369,11 +369,12 @@ class AirtableConnector(LoadConnector):
         # Process records in parallel batches using ThreadPoolExecutor
         PARALLEL_BATCH_SIZE = 8
         max_workers = min(PARALLEL_BATCH_SIZE, len(records))
+        record_documents: list[Document] = []
 
         # Process records in batches
         for i in range(0, len(records), PARALLEL_BATCH_SIZE):
             batch_records = records[i : i + PARALLEL_BATCH_SIZE]
-            record_documents: list[Document] = []
+            record_documents = []
 
             with ThreadPoolExecutor(max_workers=max_workers) as executor:
                 # Submit batch tasks
diff --git a/backend/onyx/connectors/salesforce/doc_conversion.py b/backend/onyx/connectors/salesforce/doc_conversion.py
index e6acaf2e0c..c9f48a9ec9 100644
--- a/backend/onyx/connectors/salesforce/doc_conversion.py
+++ b/backend/onyx/connectors/salesforce/doc_conversion.py
@@ -59,6 +59,7 @@ def _clean_salesforce_dict(data: dict | list) -> dict | list:
     elif isinstance(data, list):
         filtered_list = []
         for item in data:
+            filtered_item: dict | list
             if isinstance(item, (dict, list)):
                 filtered_item = _clean_salesforce_dict(item)
                 # Only add non-empty dictionaries or lists
diff --git a/backend/onyx/db/document_set.py b/backend/onyx/db/document_set.py
index 6383a6c02c..bf9d6d38db 100644
--- a/backend/onyx/db/document_set.py
+++ b/backend/onyx/db/document_set.py
@@ -221,6 +221,7 @@ def insert_document_set(
             group_ids=document_set_creation_request.groups or [],
         )
 
+    new_document_set_row: DocumentSetDBModel
     try:
         new_document_set_row = DocumentSetDBModel(
             name=document_set_creation_request.name,
diff --git a/backend/onyx/file_processing/extract_file_text.py b/backend/onyx/file_processing/extract_file_text.py
index efdeeb5469..cebd52b73b 100644
--- a/backend/onyx/file_processing/extract_file_text.py
+++ b/backend/onyx/file_processing/extract_file_text.py
@@ -365,7 +365,7 @@ def extract_file_text(
                     f"Failed to process with Unstructured: {str(unstructured_error)}. Falling back to normal processing."
                 )
                 # Fall through to normal processing
-
+        final_extension: str
         if file_name or extension:
             if extension is not None:
                 final_extension = extension
diff --git a/backend/onyx/indexing/chunker.py b/backend/onyx/indexing/chunker.py
index f95fe86e31..e42dafb293 100644
--- a/backend/onyx/indexing/chunker.py
+++ b/backend/onyx/indexing/chunker.py
@@ -223,6 +223,8 @@ class Chunker:
                 large_chunk_id=None,
             )
 
+        section_link_text: str
+
         for section_idx, section in enumerate(document.sections):
             section_text = clean_text(section.text)
             section_link_text = section.link or ""
diff --git a/backend/onyx/onyxbot/slack/utils.py b/backend/onyx/onyxbot/slack/utils.py
index f8f3ad845a..4a940c37a1 100644
--- a/backend/onyx/onyxbot/slack/utils.py
+++ b/backend/onyx/onyxbot/slack/utils.py
@@ -518,7 +518,7 @@ def read_slack_thread(
             message_type = MessageType.USER
         else:
             self_slack_bot_id = get_onyx_bot_slack_bot_id(client)
-
+            blocks: Any
             if reply.get("user") == self_slack_bot_id:
                 # OnyxBot response
                 message_type = MessageType.ASSISTANT
diff --git a/backend/onyx/redis/redis_connector_doc_perm_sync.py b/backend/onyx/redis/redis_connector_doc_perm_sync.py
index 7e58736205..538552ed84 100644
--- a/backend/onyx/redis/redis_connector_doc_perm_sync.py
+++ b/backend/onyx/redis/redis_connector_doc_perm_sync.py
@@ -1,5 +1,6 @@
 import time
 from datetime import datetime
+from typing import Any
 from typing import cast
 from uuid import uuid4
 
@@ -95,7 +96,7 @@ class RedisConnectorPermissionSync:
     @property
     def payload(self) -> RedisConnectorPermissionSyncPayload | None:
         # read related data and evaluate/print task progress
-        fence_bytes = cast(bytes, self.redis.get(self.fence_key))
+        fence_bytes = cast(Any, self.redis.get(self.fence_key))
         if fence_bytes is None:
             return None
 
diff --git a/backend/onyx/redis/redis_connector_ext_group_sync.py b/backend/onyx/redis/redis_connector_ext_group_sync.py
index 2f0783dbcc..54654bb713 100644
--- a/backend/onyx/redis/redis_connector_ext_group_sync.py
+++ b/backend/onyx/redis/redis_connector_ext_group_sync.py
@@ -1,4 +1,5 @@
 from datetime import datetime
+from typing import Any
 from typing import cast
 
 import redis
@@ -82,7 +83,7 @@ class RedisConnectorExternalGroupSync:
     @property
     def payload(self) -> RedisConnectorExternalGroupSyncPayload | None:
         # read related data and evaluate/print task progress
-        fence_bytes = cast(bytes, self.redis.get(self.fence_key))
+        fence_bytes = cast(Any, self.redis.get(self.fence_key))
         if fence_bytes is None:
             return None
 
diff --git a/backend/onyx/redis/redis_connector_index.py b/backend/onyx/redis/redis_connector_index.py
index 215468f352..b8d72049a6 100644
--- a/backend/onyx/redis/redis_connector_index.py
+++ b/backend/onyx/redis/redis_connector_index.py
@@ -1,4 +1,5 @@
 from datetime import datetime
+from typing import Any
 from typing import cast
 from uuid import uuid4
 
@@ -89,7 +90,7 @@ class RedisConnectorIndex:
     @property
     def payload(self) -> RedisConnectorIndexPayload | None:
         # read related data and evaluate/print task progress
-        fence_bytes = cast(bytes, self.redis.get(self.fence_key))
+        fence_bytes = cast(Any, self.redis.get(self.fence_key))
         if fence_bytes is None:
             return None
 
diff --git a/backend/onyx/server/manage/users.py b/backend/onyx/server/manage/users.py
index 3ef0faf393..7e3dd1f6d4 100644
--- a/backend/onyx/server/manage/users.py
+++ b/backend/onyx/server/manage/users.py
@@ -271,6 +271,8 @@ def bulk_invite_users(
 
     tenant_id = CURRENT_TENANT_ID_CONTEXTVAR.get()
     new_invited_emails = []
+    email: str
+
     try:
         for email in emails:
             email_info = validate_email(email)
diff --git a/backend/scripts/chat_feedback_dump.py b/backend/scripts/chat_feedback_dump.py
index 6fe9cbc7df..98d9237f11 100644
--- a/backend/scripts/chat_feedback_dump.py
+++ b/backend/scripts/chat_feedback_dump.py
@@ -198,6 +198,7 @@ def process_all_chat_feedback(onyx_url: str, api_key: str | None) -> None:
         r_sessions = get_chat_sessions(onyx_url, headers, user_id)
         logger.info(f"user={user_id} num_sessions={len(r_sessions.sessions)}")
         for session in r_sessions.sessions:
+            s: ChatSessionSnapshot
             try:
                 s = get_session_history(onyx_url, headers, session.id)
             except requests.exceptions.HTTPError:
diff --git a/backend/tests/daily/connectors/confluence/test_confluence_basic.py b/backend/tests/daily/connectors/confluence/test_confluence_basic.py
index 5462a66177..26cfbcf542 100644
--- a/backend/tests/daily/connectors/confluence/test_confluence_basic.py
+++ b/backend/tests/daily/connectors/confluence/test_confluence_basic.py
@@ -6,6 +6,7 @@ from unittest.mock import patch
 import pytest
 
 from onyx.connectors.confluence.connector import ConfluenceConnector
+from onyx.connectors.models import Document
 
 
 @pytest.fixture
@@ -41,6 +42,10 @@ def test_confluence_connector_basic(
 
     assert len(doc_batch) == 3
 
+    page_within_a_page_doc: Document | None = None
+    page_doc: Document | None = None
+    txt_doc: Document | None = None
+
     for doc in doc_batch:
         if doc.semantic_identifier == "DailyConnectorTestSpace Home":
             page_doc = doc
@@ -49,6 +54,7 @@ def test_confluence_connector_basic(
         elif doc.semantic_identifier == "Page Within A Page":
             page_within_a_page_doc = doc
 
+    assert page_within_a_page_doc is not None
     assert page_within_a_page_doc.semantic_identifier == "Page Within A Page"
     assert page_within_a_page_doc.primary_owners
     assert page_within_a_page_doc.primary_owners[0].email == "hagen@danswer.ai"
@@ -62,6 +68,7 @@ def test_confluence_connector_basic(
         == "https://danswerai.atlassian.net/wiki/spaces/DailyConne/pages/200769540/Page+Within+A+Page"
     )
 
+    assert page_doc is not None
     assert page_doc.semantic_identifier == "DailyConnectorTestSpace Home"
     assert page_doc.metadata["labels"] == ["testlabel"]
     assert page_doc.primary_owners
@@ -75,6 +82,7 @@ def test_confluence_connector_basic(
         == "https://danswerai.atlassian.net/wiki/spaces/DailyConne/overview"
     )
 
+    assert txt_doc is not None
     assert txt_doc.semantic_identifier == "small-file.txt"
     assert len(txt_doc.sections) == 1
     assert txt_doc.sections[0].text == "small"
diff --git a/backend/tests/daily/connectors/gmail/test_gmail_connector.py b/backend/tests/daily/connectors/gmail/test_gmail_connector.py
index d746f86bd8..1d58344e67 100644
--- a/backend/tests/daily/connectors/gmail/test_gmail_connector.py
+++ b/backend/tests/daily/connectors/gmail/test_gmail_connector.py
@@ -110,6 +110,8 @@ def test_docs_retrieval(
 
     for doc in retrieved_docs:
         id = doc.id
+        retrieved_primary_owner_emails: set[str | None] = set()
+        retrieved_secondary_owner_emails: set[str | None] = set()
         if doc.primary_owners:
             retrieved_primary_owner_emails = set(
                 [owner.email for owner in doc.primary_owners]
diff --git a/backend/tests/integration/common_utils/managers/user.py b/backend/tests/integration/common_utils/managers/user.py
index 63a6c887d3..03539ce566 100644
--- a/backend/tests/integration/common_utils/managers/user.py
+++ b/backend/tests/integration/common_utils/managers/user.py
@@ -165,6 +165,7 @@ class UserManager:
         target_status: bool,
         user_performing_action: DATestUser,
     ) -> DATestUser:
+        url_substring: str
         if target_status is True:
             url_substring = "activate"
         elif target_status is False: