diff --git a/swh/storage/interface.py b/swh/storage/interface.py
--- a/swh/storage/interface.py
+++ b/swh/storage/interface.py
@@ -5,17 +5,7 @@
 
 import datetime
 from enum import Enum
-from typing import (
-    TYPE_CHECKING,
-    Any,
-    Dict,
-    Iterable,
-    List,
-    Optional,
-    Sequence,
-    Tuple,
-    TypeVar,
-)
+from typing import Any, Dict, Iterable, List, Optional, Sequence, Tuple, TypeVar
 
 import attr
 from typing_extensions import Protocol, TypedDict, runtime_checkable
@@ -44,9 +34,6 @@
 )
 from swh.model.swhids import ExtendedSWHID, ObjectType
 
-if TYPE_CHECKING:
-    from swh.storage.writer import JournalWriter
-
 
 class ListOrder(Enum):
     """Specifies the order for paginated endpoints returning sorted results."""
@@ -89,8 +76,6 @@
 
 @runtime_checkable
 class StorageInterface(Protocol):
-    journal_writer: Optional["JournalWriter"]
-
     @remote_api_endpoint("check_config")
     def check_config(self, *, check_write: bool) -> bool:
         """Check that the storage is configured and ready to go."""
diff --git a/swh/storage/tests/test_backfill.py b/swh/storage/tests/test_backfill.py
--- a/swh/storage/tests/test_backfill.py
+++ b/swh/storage/tests/test_backfill.py
@@ -243,8 +243,7 @@
     for object_type, objects in TEST_OBJECTS.items():
         method = getattr(storage, object_type + "_add")
         method(objects)
-    assert storage.journal_writer is not None
-    storage.journal_writer.journal.flush()
+    storage.journal_writer.journal.flush()  # type: ignore[attr-defined]
 
     # now apply the backfiller on the storage to fill the journal under prefix2
     backfiller_config = {
diff --git a/swh/storage/tests/test_kafka_writer.py b/swh/storage/tests/test_kafka_writer.py
--- a/swh/storage/tests/test_kafka_writer.py
+++ b/swh/storage/tests/test_kafka_writer.py
@@ -59,8 +59,7 @@
             expected_messages += len(objs)
         else:
             assert False, obj_type
-    assert storage.journal_writer is not None
-    storage.journal_writer.journal.flush()
+    storage.journal_writer.journal.flush()  # type: ignore[attr-defined]
 
     existing_topics = set(
         topic
@@ -121,8 +120,7 @@
         method = getattr(storage, obj_type + "_add")
         method(objs)
         expected_messages += len(objs)
-    assert storage.journal_writer is not None
-    storage.journal_writer.journal.flush()
+    storage.journal_writer.journal.flush()  # type: ignore[attr-defined]
 
     existing_topics = set(
         topic
diff --git a/swh/storage/tests/test_replay.py b/swh/storage/tests/test_replay.py
--- a/swh/storage/tests/test_replay.py
+++ b/swh/storage/tests/test_replay.py
@@ -359,8 +359,7 @@
         method = getattr(storage, obj_type + "_add")
         method(objs)
         nb_sent += len(objs)
-    assert storage.journal_writer is not None
-    storage.journal_writer.journal.flush()
+    storage.journal_writer.journal.flush()  # type: ignore[attr-defined]
 
     # Fill a destination storage from Kafka, potentially using privileged topics
     dst_storage = get_storage(cls="memory")