diff --git a/swh/storage/cassandra/storage.py b/swh/storage/cassandra/storage.py
--- a/swh/storage/cassandra/storage.py
+++ b/swh/storage/cassandra/storage.py
@@ -17,13 +17,8 @@
     Revision, Release, Directory, DirectoryEntry, Content, SkippedContent,
     OriginVisit, Snapshot, Origin
 )
-try:
-    from swh.journal.writer import get_journal_writer
-except ImportError:
-    get_journal_writer = None  # type: ignore
-    # mypy limitation, see https://github.com/python/mypy/issues/1153
-
 from swh.storage.objstorage import ObjStorage
+from swh.storage.writer import JournalWriter
 
 from .. import HashCollision
 from ..exc import StorageArgumentException
@@ -47,11 +42,7 @@
     def __init__(self, hosts, keyspace, objstorage,
                  port=9042, journal_writer=None):
         self._cql_runner = CqlRunner(hosts, keyspace, port)
-
-        if journal_writer:
-            self.journal_writer = get_journal_writer(**journal_writer)
-        else:
-            self.journal_writer = None
+        self.journal_writer = JournalWriter(journal_writer)
         self.objstorage = ObjStorage(objstorage)
 
     def check_config(self, *, check_write):
@@ -64,12 +55,7 @@
         contents = [c for c in contents
                     if not self._cql_runner.content_get_from_pk(c.to_dict())]
 
-        if self.journal_writer:
-            for content in contents:
-                cont = content.to_dict()
-                if 'data' in cont:
-                    del cont['data']
-                self.journal_writer.write_addition('content', cont)
+        self.journal_writer.content_add(contents)
 
         if with_data:
             # First insert to the objstorage, if the endpoint is
@@ -249,12 +235,7 @@
             c for c in contents
             if not self._cql_runner.skipped_content_get_from_pk(c.to_dict())]
 
-        if self.journal_writer:
-            for content in contents:
-                cont = content.to_dict()
-                if 'data' in cont:
-                    del cont['data']
-                self.journal_writer.write_addition('content', cont)
+        self.journal_writer.skipped_content_add(contents)
 
         for content in contents:
             # Add to index tables
@@ -285,8 +266,7 @@
         missing = self.directory_missing([dir_.id for dir_ in directories])
         directories = [dir_ for dir_ in directories if dir_.id in missing]
 
-        if self.journal_writer:
-            self.journal_writer.write_additions('directory', directories)
+        self.journal_writer.directory_add(directories)
 
         for directory in directories:
             # Add directory entries to the 'directory_entry' table
@@ -390,8 +370,7 @@
         missing = self.revision_missing([rev.id for rev in revisions])
         revisions = [rev for rev in revisions if rev.id in missing]
 
-        if self.journal_writer:
-            self.journal_writer.write_additions('revision', revisions)
+        self.journal_writer.revision_add(revisions)
 
         for revision in revisions:
             revision = revision_to_db(revision)
@@ -483,8 +462,7 @@
         missing = self.release_missing([rel.id for rel in releases])
         releases = [rel for rel in releases if rel.id in missing]
 
-        if self.journal_writer:
-            self.journal_writer.write_additions('release', releases)
+        self.journal_writer.release_add(releases)
 
         for release in releases:
             if release:
@@ -516,8 +494,7 @@
         snapshots = [snp for snp in snapshots if snp.id in missing]
 
         for snapshot in snapshots:
-            if self.journal_writer:
-                self.journal_writer.write_addition('snapshot', snapshot)
+            self.journal_writer.snapshot_add(snapshot)
 
             # Add branches
             for (branch_name, branch) in snapshot.branches.items():
@@ -763,8 +740,7 @@
         if known_origin:
             origin_url = known_origin['url']
         else:
-            if self.journal_writer:
-                self.journal_writer.write_addition('origin', origin)
+            self.journal_writer.origin_add_one(origin)
 
             self._cql_runner.origin_add_one(origin)
             origin_url = origin.url
@@ -797,9 +773,7 @@
             })
         except (KeyError, TypeError, ValueError) as e:
             raise StorageArgumentException(*e.args)
-
-        if self.journal_writer:
-            self.journal_writer.write_addition('origin_visit', visit)
+        self.journal_writer.origin_visit_add(visit)
 
         self._cql_runner.origin_visit_add_one(visit)
 
@@ -835,8 +809,7 @@
         except (KeyError, TypeError, ValueError) as e:
             raise StorageArgumentException(*e.args)
 
-        if self.journal_writer:
-            self.journal_writer.write_update('origin_visit', visit)
+        self.journal_writer.origin_visit_update(visit)
 
         self._cql_runner.origin_visit_update(origin_url, visit_id, updates)
 
@@ -846,9 +819,7 @@
             if isinstance(visit['date'], str):
                 visit['date'] = dateutil.parser.parse(visit['date'])
 
-        if self.journal_writer:
-            for visit in visits:
-                self.journal_writer.write_addition('origin_visit', visit)
+        self.journal_writer.origin_visit_upsert(visits)
 
         for visit in visits:
             visit = visit.copy()
diff --git a/swh/storage/in_memory.py b/swh/storage/in_memory.py
--- a/swh/storage/in_memory.py
+++ b/swh/storage/in_memory.py
@@ -26,9 +26,10 @@
 
 from . import HashCollision
 from .exc import StorageArgumentException
-from .storage import get_journal_writer
+
 from .converters import origin_url_to_sha1
 from .utils import get_partition_bounds_bytes
+from .writer import JournalWriter
 
 # Max block size of contents to return
 BULK_BLOCK_CONTENT_LEN_MAX = 10000
@@ -46,11 +47,7 @@
         self._skipped_content_indexes = defaultdict(lambda: defaultdict(set))
 
         self.reset()
-
-        if journal_writer:
-            self.journal_writer = get_journal_writer(**journal_writer)
-        else:
-            self.journal_writer = None
+        self.journal_writer = JournalWriter(journal_writer)
 
     def reset(self):
         self._directories = {}
@@ -77,10 +74,7 @@
 
     def _content_add(
             self, contents: Iterable[Content], with_data: bool) -> Dict:
-        if self.journal_writer:
-            for content in contents:
-                content = attr.evolve(content, data=None)
-                self.journal_writer.write_addition('content', content)
+        self.journal_writer.content_add(contents)
 
         content_add = 0
         content_add_bytes = 0
@@ -125,9 +119,7 @@
         return self._content_add(content, with_data=True)
 
     def content_update(self, content, keys=[]):
-        if self.journal_writer:
-            raise NotImplementedError(
-                'content_update is not yet supported with a journal_writer.')
+        self.journal_writer.content_update(content)
 
         for cont_update in content:
             cont_update = cont_update.copy()
@@ -260,9 +252,7 @@
         return random.choice(list(self._content_indexes['sha1_git']))
 
     def _skipped_content_add(self, contents: Iterable[SkippedContent]) -> Dict:
-        if self.journal_writer:
-            for cont in contents:
-                self.journal_writer.write_addition('content', cont)
+        self.journal_writer.skipped_content_add(contents)
 
         summary = {
             'skipped_content:add': 0
@@ -301,20 +291,16 @@
         return self._skipped_content_add(content)
 
     def directory_add(self, directories: Iterable[Directory]) -> Dict:
-        directories = list(directories)
-        if self.journal_writer:
-            self.journal_writer.write_additions(
-                'directory',
-                (dir_ for dir_ in directories
-                 if dir_.id not in self._directories))
+        directories = [dir_ for dir_ in directories
+                       if dir_.id not in self._directories]
+        self.journal_writer.directory_add(directories)
 
         count = 0
         for directory in directories:
-            if directory.id not in self._directories:
-                count += 1
-                self._directories[directory.id] = directory
-                self._objects[directory.id].append(
-                    ('directory', directory.id))
+            count += 1
+            self._directories[directory.id] = directory
+            self._objects[directory.id].append(
+                ('directory', directory.id))
 
         return {'directory:add': count}
 
@@ -392,24 +378,20 @@
                 first_item['target'], paths[1:], prefix + paths[0] + b'/')
 
     def revision_add(self, revisions: Iterable[Revision]) -> Dict:
-        revisions = list(revisions)
-        if self.journal_writer:
-            self.journal_writer.write_additions(
-                'revision',
-                (rev for rev in revisions
-                 if rev.id not in self._revisions))
+        revisions = [rev for rev in revisions
+                     if rev.id not in self._revisions]
+        self.journal_writer.revision_add(revisions)
 
         count = 0
         for revision in revisions:
-            if revision.id not in self._revisions:
-                revision = attr.evolve(
-                    revision,
-                    committer=self._person_add(revision.committer),
-                    author=self._person_add(revision.author))
-                self._revisions[revision.id] = revision
-                self._objects[revision.id].append(
-                    ('revision', revision.id))
-                count += 1
+            revision = attr.evolve(
+                revision,
+                committer=self._person_add(revision.committer),
+                author=self._person_add(revision.author))
+            self._revisions[revision.id] = revision
+            self._objects[revision.id].append(
+                ('revision', revision.id))
+            count += 1
 
         return {'revision:add': count}
 
@@ -448,22 +430,18 @@
         return random.choice(list(self._revisions))
 
     def release_add(self, releases: Iterable[Release]) -> Dict:
-        releases = list(releases)
-        if self.journal_writer:
-            self.journal_writer.write_additions(
-                'release',
-                (rel for rel in releases
-                 if rel.id not in self._releases))
+        releases = [rel for rel in releases
+                    if rel.id not in self._releases]
+        self.journal_writer.release_add(releases)
 
         count = 0
         for rel in releases:
-            if rel.id not in self._releases:
-                if rel.author:
-                    self._person_add(rel.author)
-                self._objects[rel.id].append(
-                    ('release', rel.id))
-                self._releases[rel.id] = rel
-                count += 1
+            if rel.author:
+                self._person_add(rel.author)
+            self._objects[rel.id].append(
+                ('release', rel.id))
+            self._releases[rel.id] = rel
+            count += 1
 
         return {'release:add': count}
 
@@ -485,9 +463,7 @@
         snapshots = (snap for snap in snapshots
                      if snap.id not in self._snapshots)
         for snapshot in snapshots:
-            if self.journal_writer:
-                self.journal_writer.write_addition('snapshot', snapshot)
-
+            self.journal_writer.snapshot_add(snapshot)
             sorted_branch_names = sorted(snapshot.branches)
             self._snapshots[snapshot.id] = (snapshot, sorted_branch_names)
             self._objects[snapshot.id].append(('snapshot', snapshot.id))
@@ -699,9 +675,7 @@
 
     def origin_add_one(self, origin: Origin) -> str:
         if origin.url not in self._origins:
-            if self.journal_writer:
-                self.journal_writer.write_addition('origin', origin)
-
+            self.journal_writer.origin_add_one(origin)
             # generate an origin_id because it is needed by origin_get_range.
             # TODO: remove this when we remove origin_get_range
             origin_id = len(self._origins) + 1
@@ -752,8 +726,7 @@
             self._objects[(origin_url, visit_id)].append(
                 ('origin_visit', None))
 
-            if self.journal_writer:
-                self.journal_writer.write_addition('origin_visit', visit)
+            self.journal_writer.origin_visit_add(visit)
 
         return visit_ret
 
@@ -783,8 +756,7 @@
         except (KeyError, TypeError, ValueError) as e:
             raise StorageArgumentException(*e.args)
 
-        if self.journal_writer:
-            self.journal_writer.write_update('origin_visit', visit)
+        self.journal_writer.origin_visit_update(visit)
 
         self._origin_visits[origin_url][visit_id-1] = visit
 
@@ -798,9 +770,7 @@
         except (KeyError, TypeError, ValueError) as e:
             raise StorageArgumentException(*e.args)
 
-        if self.journal_writer:
-            for visit in visits:
-                self.journal_writer.write_addition('origin_visit', visit)
+        self.journal_writer.origin_visit_upsert(visits)
 
         for visit in visits:
             visit_id = visit.visit
diff --git a/swh/storage/storage.py b/swh/storage/storage.py
--- a/swh/storage/storage.py
+++ b/swh/storage/storage.py
@@ -25,11 +25,6 @@
     Snapshot, Origin, SHA1_SIZE
 )
 from swh.model.hashutil import DEFAULT_ALGORITHMS, hash_to_bytes, hash_to_hex
-try:
-    from swh.journal.writer import get_journal_writer
-except ImportError:
-    get_journal_writer = None  # type: ignore
-    # mypy limitation, see https://github.com/python/mypy/issues/1153
 from swh.storage.objstorage import ObjStorage
 
 from . import converters, HashCollision
@@ -39,6 +34,7 @@
 from .algos import diff
 from .metrics import timed, send_metric, process_metrics
 from .utils import get_partition_bounds_bytes
+from .writer import JournalWriter
 
 
 # Max block size of contents to return
@@ -95,14 +91,7 @@
         except psycopg2.OperationalError as e:
             raise StorageDBError(e)
 
-        if journal_writer:
-            if get_journal_writer is None:
-                raise EnvironmentError(
-                    'You need the swh.journal package to use the '
-                    'journal_writer feature')
-            self.journal_writer = get_journal_writer(**journal_writer)
-        else:
-            self.journal_writer = None
+        self.journal_writer = JournalWriter(journal_writer)
         self.objstorage = ObjStorage(objstorage)
 
     def get_db(self):
@@ -186,17 +175,13 @@
     def content_add(
             self, content: Iterable[Content], db=None, cur=None) -> Dict:
         now = datetime.datetime.now(tz=datetime.timezone.utc)
-        content = [attr.evolve(c, ctime=now) for c in content]
+        contents = [attr.evolve(c, ctime=now) for c in content]
 
         missing = list(self.content_missing(
-            map(Content.to_dict, content), key_hash='sha1_git'))
-        content = [c for c in content if c.sha1_git in missing]
+            map(Content.to_dict, contents), key_hash='sha1_git'))
+        contents = [c for c in contents if c.sha1_git in missing]
 
-        if self.journal_writer:
-            for item in content:
-                if item.data:
-                    item = attr.evolve(item, data=None)
-                self.journal_writer.write_addition('content', item)
+        self.journal_writer.content_add(contents)
 
         def add_to_objstorage():
             """Add to objstorage the new missing_content
@@ -206,20 +191,20 @@
                 objstorage. Content present twice is only sent once.
 
             """
-            summary = self.objstorage.content_add(content)
+            summary = self.objstorage.content_add(contents)
             return summary['content:add:bytes']
 
         with ThreadPoolExecutor(max_workers=1) as executor:
             added_to_objstorage = executor.submit(add_to_objstorage)
 
-            self._content_add_metadata(db, cur, content)
+            self._content_add_metadata(db, cur, contents)
 
             # Wait for objstorage addition before returning from the
             # transaction, bubbling up any exception
             content_bytes_added = added_to_objstorage.result()
 
         return {
-            'content:add': len(content),
+            'content:add': len(contents),
             'content:add:bytes': content_bytes_added,
         }
 
@@ -228,10 +213,7 @@
     def content_update(self, content, keys=[], db=None, cur=None):
         # TODO: Add a check on input keys. How to properly implement
         # this? We don't know yet the new columns.
-
-        if self.journal_writer:
-            raise NotImplementedError(
-                'content_update is not yet supported with a journal_writer.')
+        self.journal_writer.content_update(content)
 
         db.mktemp('content', cur)
         select_keys = list(set(db.content_get_metadata_keys).union(set(keys)))
@@ -245,20 +227,16 @@
     @db_transaction()
     def content_add_metadata(self, content: Iterable[Content],
                              db=None, cur=None) -> Dict:
-        content = list(content)
+        contents = list(content)
         missing = self.content_missing(
-            (c.to_dict() for c in content), key_hash='sha1_git')
-        content = [c for c in content if c.sha1_git in missing]
+            (c.to_dict() for c in contents), key_hash='sha1_git')
+        contents = [c for c in contents if c.sha1_git in missing]
 
-        if self.journal_writer:
-            for item in itertools.chain(content):
-                assert item.data is None
-                self.journal_writer.write_addition('content', item)
-
-        self._content_add_metadata(db, cur, content)
+        self.journal_writer.content_add_metadata(contents)
+        self._content_add_metadata(db, cur, contents)
 
         return {
-            'content:add': len(content),
+            'content:add': len(contents),
         }
 
     @timed
@@ -429,10 +407,7 @@
                               for algo in DEFAULT_ALGORITHMS)
                           for missing_content in missing_contents)]
 
-        if self.journal_writer:
-            for item in content:
-                self.journal_writer.write_addition('content', item)
-
+        self.journal_writer.skipped_content_add(content)
         self._skipped_content_add_metadata(db, cur, content)
 
         return {
@@ -473,11 +448,10 @@
         if not dirs_missing:
             return summary
 
-        if self.journal_writer:
-            self.journal_writer.write_additions(
-                'directory',
-                (dir_ for dir_ in directories
-                 if dir_.id in dirs_missing))
+        self.journal_writer.directory_add(
+            dir_ for dir_ in directories
+            if dir_.id in dirs_missing
+        )
 
         # Copy directory ids
         dirs_missing_dict = ({'id': dir} for dir in dirs_missing)
@@ -557,8 +531,7 @@
             revision for revision in revisions
             if revision.id in revisions_missing]
 
-        if self.journal_writer:
-            self.journal_writer.write_additions('revision', revisions_filtered)
+        self.journal_writer.revision_add(revisions_filtered)
 
         revisions_filtered = \
             list(map(converters.revision_to_db, revisions_filtered))
@@ -644,8 +617,7 @@
             if release.id in releases_missing
         ]
 
-        if self.journal_writer:
-            self.journal_writer.write_additions('release', releases_filtered)
+        self.journal_writer.release_add(releases_filtered)
 
         releases_filtered = \
             list(map(converters.release_to_db, releases_filtered))
@@ -713,8 +685,7 @@
                 except VALIDATION_EXCEPTIONS + (KeyError,) as e:
                     raise StorageArgumentException(*e.args)
 
-                if self.journal_writer:
-                    self.journal_writer.write_addition('snapshot', snapshot)
+                self.journal_writer.snapshot_add(snapshot)
 
                 db.snapshot_add(snapshot.id, cur)
                 count += 1
@@ -830,13 +801,18 @@
         with convert_validation_exceptions():
             visit_id = db.origin_visit_add(origin_url, date, type, cur)
 
-        if self.journal_writer:
-            # We can write to the journal only after inserting to the
-            # DB, because we want the id of the visit
-            self.journal_writer.write_addition('origin_visit', {
-                'origin': origin_url, 'date': date, 'type': type,
-                'visit': visit_id,
-                'status': 'ongoing', 'metadata': None, 'snapshot': None})
+        # We can write to the journal only after inserting to the
+        # DB, because we want the id of the visit
+        visit = {
+            'origin': origin_url,
+            'date': date,
+            'type': type,
+            'visit': visit_id,
+            'status': 'ongoing',
+            'metadata': None,
+            'snapshot': None
+        }
+        self.journal_writer.origin_visit_add(visit)
 
         send_metric('origin_visit:add', count=1, method_name='origin_visit')
         return {
@@ -871,9 +847,8 @@
             updates['snapshot'] = snapshot
 
         if updates:
-            if self.journal_writer:
-                self.journal_writer.write_update('origin_visit', {
-                    **visit, **updates})
+            updated_visit = {**visit, **updates}
+            self.journal_writer.origin_visit_update(updated_visit)
 
             with convert_validation_exceptions():
                 db.origin_visit_update(origin_url, visit_id, updates, cur)
@@ -890,9 +865,7 @@
                     "visit['origin'] must be a string, not %r"
                     % (visit['origin'],))
 
-        if self.journal_writer:
-            for visit in visits:
-                self.journal_writer.write_addition('origin_visit', visit)
+        self.journal_writer.origin_visit_upsert(visits)
 
         for visit in visits:
             # TODO: upsert them all in a single query
@@ -1055,8 +1028,7 @@
         if origin_url:
             return origin_url
 
-        if self.journal_writer:
-            self.journal_writer.write_addition('origin', origin)
+        self.journal_writer.origin_add_one(origin)
 
         origins = db.origin_add(origin.url, cur)
         send_metric('origin:add', count=len(origins), method_name='origin_add')
diff --git a/swh/storage/tests/test_api_client.py b/swh/storage/tests/test_api_client.py
--- a/swh/storage/tests/test_api_client.py
+++ b/swh/storage/tests/test_api_client.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2015-2018  The Software Heritage developers
+# Copyright (C) 2015-2020  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
@@ -63,6 +63,7 @@
 
 class TestStorage(_TestStorage):
     def test_content_update(self, swh_storage, app_server):
-        swh_storage.journal_writer = None  # TODO, journal_writer not supported
-        with patch.object(server.storage.storage, 'journal_writer', None):
+        # TODO, journal_writer not supported
+        swh_storage.journal_writer.journal = None
+        with patch.object(server.storage.journal_writer, 'journal', None):
             super().test_content_update(swh_storage)
diff --git a/swh/storage/tests/test_storage.py b/swh/storage/tests/test_storage.py
--- a/swh/storage/tests/test_storage.py
+++ b/swh/storage/tests/test_storage.py
@@ -151,7 +151,7 @@
 
         expected_cont = data.cont
         del expected_cont['data']
-        journal_objects = list(swh_storage.journal_writer.objects)
+        journal_objects = list(swh_storage.journal_writer.journal.objects)
         for (obj_type, obj) in journal_objects:
             assert insertion_start_time <= obj['ctime']
             assert obj['ctime'] <= insertion_end_time
@@ -241,14 +241,14 @@
             'content:add': 1,
             'content:add:bytes': data.cont['length'],
             }
-        assert len(swh_storage.journal_writer.objects) == 1
+        assert len(swh_storage.journal_writer.journal.objects) == 1
 
         actual_result = swh_storage.content_add([data.cont, data.cont2])
         assert actual_result == {
             'content:add': 1,
             'content:add:bytes': data.cont2['length'],
             }
-        assert 2 <= len(swh_storage.journal_writer.objects) <= 3
+        assert 2 <= len(swh_storage.journal_writer.journal.objects) <= 3
 
         assert len(swh_storage.content_find(data.cont)) == 1
         assert len(swh_storage.content_find(data.cont2)) == 1
@@ -269,7 +269,7 @@
 
     def test_content_update(self, swh_storage):
         if hasattr(swh_storage, 'storage'):
-            swh_storage.storage.journal_writer = None  # TODO, not supported
+            swh_storage.journal_writer.journal = None  # TODO, not supported
 
         cont = copy.deepcopy(data.cont)
 
@@ -300,7 +300,8 @@
             cont['sha1']: [expected_cont]
         }
 
-        assert list(swh_storage.journal_writer.objects) == [('content', cont)]
+        assert list(swh_storage.journal_writer.journal.objects) == [
+            ('content', cont)]
 
     def test_content_add_metadata_different_input(self, swh_storage):
         cont = data.cont
@@ -551,7 +552,7 @@
         actual_result = swh_storage.directory_add([data.dir])
         assert actual_result == {'directory:add': 1}
 
-        assert list(swh_storage.journal_writer.objects) == \
+        assert list(swh_storage.journal_writer.journal.objects) == \
             [('directory', data.dir)]
 
         actual_data = list(swh_storage.directory_ls(data.dir['id']))
@@ -573,7 +574,7 @@
         actual_result = swh_storage.directory_add(directories=_dir_gen())
         assert actual_result == {'directory:add': 1}
 
-        assert list(swh_storage.journal_writer.objects) == \
+        assert list(swh_storage.journal_writer.journal.objects) == \
             [('directory', data.dir)]
 
         swh_storage.refresh_stat_counters()
@@ -599,13 +600,13 @@
         actual_result = swh_storage.directory_add([data.dir])
         assert actual_result == {'directory:add': 1}
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('directory', data.dir)]
 
         actual_result = swh_storage.directory_add([data.dir])
         assert actual_result == {'directory:add': 0}
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('directory', data.dir)]
 
     def test_directory_get_recursive(self, swh_storage):
@@ -616,7 +617,7 @@
             [data.dir, data.dir2, data.dir3])
         assert actual_result == {'directory:add': 3}
 
-        assert list(swh_storage.journal_writer.objects) == [
+        assert list(swh_storage.journal_writer.journal.objects) == [
             ('directory', data.dir),
             ('directory', data.dir2),
             ('directory', data.dir3)]
@@ -653,7 +654,7 @@
             [data.dir, data.dir2, data.dir3])
         assert actual_result == {'directory:add': 3}
 
-        assert list(swh_storage.journal_writer.objects) == [
+        assert list(swh_storage.journal_writer.journal.objects) == [
             ('directory', data.dir),
             ('directory', data.dir2),
             ('directory', data.dir3)]
@@ -767,7 +768,7 @@
 
         normalized_revision = Revision.from_dict(data.revision).to_dict()
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('revision', normalized_revision)]
 
         # already there so nothing added
@@ -825,14 +826,14 @@
         normalized_revision = Revision.from_dict(data.revision).to_dict()
         normalized_revision2 = Revision.from_dict(data.revision2).to_dict()
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('revision', normalized_revision)]
 
         actual_result = swh_storage.revision_add(
             [data.revision, data.revision2])
         assert actual_result == {'revision:add': 1}
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('revision', normalized_revision),
                 ('revision', normalized_revision2)]
 
@@ -877,7 +878,7 @@
         normalized_revision3 = Revision.from_dict(data.revision3).to_dict()
         normalized_revision4 = Revision.from_dict(data.revision4).to_dict()
 
-        assert list(swh_storage.journal_writer.objects) == [
+        assert list(swh_storage.journal_writer.journal.objects) == [
             ('revision', normalized_revision3),
             ('revision', normalized_revision4)]
 
@@ -974,7 +975,7 @@
                                                    data.release2['id']])
         assert list(end_missing) == []
 
-        assert list(swh_storage.journal_writer.objects) == [
+        assert list(swh_storage.journal_writer.journal.objects) == [
             ('release', normalized_release),
             ('release', normalized_release2)]
 
@@ -996,7 +997,7 @@
         actual_result = swh_storage.release_add(_rel_gen())
         assert actual_result == {'release:add': 2}
 
-        assert list(swh_storage.journal_writer.objects) == [
+        assert list(swh_storage.journal_writer.journal.objects) == [
             ('release', normalized_release),
             ('release', normalized_release2)]
 
@@ -1015,7 +1016,7 @@
         end_missing = swh_storage.release_missing([data.release['id']])
         assert list(end_missing) == []
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('release', release)]
 
     def test_release_add_validation(self, swh_storage):
@@ -1045,13 +1046,13 @@
         normalized_release = Release.from_dict(data.release).to_dict()
         normalized_release2 = Release.from_dict(data.release2).to_dict()
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('release', normalized_release)]
 
         actual_result = swh_storage.release_add([data.release, data.release2])
         assert actual_result == {'release:add': 1}
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('release', normalized_release),
                 ('release', normalized_release2)]
 
@@ -1133,7 +1134,7 @@
             del actual_origin['id']
             del actual_origin2['id']
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('origin', actual_origin),
                 ('origin', actual_origin2)]
 
@@ -1161,7 +1162,7 @@
             del actual_origin['id']
             del actual_origin2['id']
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('origin', actual_origin),
                 ('origin', actual_origin2)]
 
@@ -1170,12 +1171,12 @@
 
     def test_origin_add_twice(self, swh_storage):
         add1 = swh_storage.origin_add([data.origin, data.origin2])
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('origin', data.origin),
                 ('origin', data.origin2)]
 
         add2 = swh_storage.origin_add([data.origin, data.origin2])
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('origin', data.origin),
                 ('origin', data.origin2)]
 
@@ -1431,7 +1432,7 @@
             'metadata': None,
             'snapshot': None,
         }
-        objects = list(swh_storage.journal_writer.objects)
+        objects = list(swh_storage.journal_writer.journal.objects)
         assert ('origin', data.origin2) in objects
         assert ('origin_visit', origin_visit) in objects
 
@@ -1494,7 +1495,7 @@
         for visit in expected_visits:
             assert visit in actual_origin_visits
 
-        objects = list(swh_storage.journal_writer.objects)
+        objects = list(swh_storage.journal_writer.journal.objects)
         assert ('origin', data.origin2) in objects
 
         for visit in expected_visits:
@@ -1667,7 +1668,7 @@
             'metadata': None,
             'snapshot': None,
         }
-        objects = list(swh_storage.journal_writer.objects)
+        objects = list(swh_storage.journal_writer.journal.objects)
         assert ('origin', data.origin) in objects
         assert ('origin', data.origin2) in objects
         assert ('origin_visit', data1) in objects
@@ -1888,7 +1889,7 @@
             'metadata': None,
             'snapshot': None,
         }
-        assert list(swh_storage.journal_writer.objects) == [
+        assert list(swh_storage.journal_writer.journal.objects) == [
             ('origin', data.origin2),
             ('origin_visit', data1),
             ('origin_visit', data2)]
@@ -1949,7 +1950,7 @@
             'metadata': None,
             'snapshot': None,
         }
-        assert list(swh_storage.journal_writer.objects) == [
+        assert list(swh_storage.journal_writer.journal.objects) == [
             ('origin', data.origin2),
             ('origin_visit', data1),
             ('origin_visit', data2)]
@@ -2126,7 +2127,7 @@
             'metadata': None,
             'snapshot': data.empty_snapshot['id'],
         }
-        assert list(swh_storage.journal_writer.objects) == \
+        assert list(swh_storage.journal_writer.journal.objects) == \
             [('origin', data.origin),
              ('origin_visit', data1),
              ('snapshot', data.empty_snapshot),
@@ -2196,13 +2197,13 @@
         actual_result = swh_storage.snapshot_add([data.empty_snapshot])
         assert actual_result == {'snapshot:add': 1}
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('snapshot', data.empty_snapshot)]
 
         actual_result = swh_storage.snapshot_add([data.snapshot])
         assert actual_result == {'snapshot:add': 1}
 
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('snapshot', data.empty_snapshot),
                 ('snapshot', data.snapshot)]
 
@@ -2438,7 +2439,7 @@
         swh_storage.origin_add_one(data.origin)
         visit_id = 54164461156
 
-        swh_storage.journal_writer.objects[:] = []
+        swh_storage.journal_writer.journal.objects[:] = []
 
         swh_storage.snapshot_add([data.snapshot])
 
@@ -2446,7 +2447,7 @@
             swh_storage.origin_visit_update(
                 origin_url, visit_id, snapshot=data.snapshot['id'])
 
-        assert list(swh_storage.journal_writer.objects) == [
+        assert list(swh_storage.journal_writer.journal.objects) == [
             ('snapshot', data.snapshot)]
 
     def test_snapshot_add_twice__by_origin_visit(self, swh_storage):
@@ -2517,7 +2518,7 @@
             'metadata': None,
             'snapshot': data.snapshot['id'],
         }
-        assert list(swh_storage.journal_writer.objects) \
+        assert list(swh_storage.journal_writer.journal.objects) \
             == [('origin', data.origin),
                 ('origin_visit', data1),
                 ('snapshot', data.snapshot),
@@ -3704,7 +3705,7 @@
     """
 
     def test_content_update_with_new_cols(self, swh_storage):
-        swh_storage.storage.journal_writer = None  # TODO, not supported
+        swh_storage.journal_writer.journal = None  # TODO, not supported
 
         with db_transaction(swh_storage) as (_, cur):
             cur.execute("""alter table content
@@ -3758,7 +3759,7 @@
 
         expected_cont = cont.copy()
         del expected_cont['data']
-        journal_objects = list(swh_storage.journal_writer.objects)
+        journal_objects = list(swh_storage.journal_writer.journal.objects)
         for (obj_type, obj) in journal_objects:
             del obj['ctime']
         assert journal_objects == [('content', expected_cont)]
@@ -3784,7 +3785,8 @@
         assert datum == (cont['sha1'], cont['sha1_git'], cont['sha256'],
                          cont['length'], 'visible')
 
-        assert list(swh_storage.journal_writer.objects) == [('content', cont)]
+        assert list(swh_storage.journal_writer.journal.objects) == [
+            ('content', cont)]
 
     def test_skipped_content_add_db(self, swh_storage):
         cont = data.skipped_cont
diff --git a/swh/storage/writer.py b/swh/storage/writer.py
new file mode 100644
--- /dev/null
+++ b/swh/storage/writer.py
@@ -0,0 +1,99 @@
+# Copyright (C) 2020 The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+from typing import Iterable, Union
+from swh.model.model import (
+    Origin, OriginVisit, Snapshot, Directory, Revision, Release, Content
+)
+
+try:
+    from swh.journal.writer import get_journal_writer
+except ImportError:
+    get_journal_writer = None  # type: ignore
+    # mypy limitation, see https://github.com/python/mypy/issues/1153
+
+
+class JournalWriter:
+    """Journal writer storage collaborator. It's in charge of adding objects to
+    the journal.
+
+    """
+    def __init__(self, journal_writer):
+        if journal_writer:
+            if get_journal_writer is None:
+                raise EnvironmentError(
+                    'You need the swh.journal package to use the '
+                    'journal_writer feature')
+            self.journal = get_journal_writer(**journal_writer)
+        else:
+            self.journal = None
+
+    def content_add(self, contents: Iterable[Content]) -> None:
+        """Add contents to the journal. Drop the data field if provided.
+
+        """
+        if not self.journal:
+            return
+        for item in contents:
+            content = item.to_dict()
+            if 'data' in content:
+                del content['data']
+            self.journal.write_addition('content', content)
+
+    def content_update(self, contents: Iterable[Content]) -> None:
+        if not self.journal:
+            return
+        raise NotImplementedError(
+            'content_update is not yet supported with a journal writer.')
+
+    def content_add_metadata(
+            self, contents: Iterable[Content]) -> None:
+        return self.content_add(contents)
+
+    def skipped_content_add(
+            self, contents: Iterable[Content]) -> None:
+        return self.content_add(contents)
+
+    def directory_add(self, directories: Iterable[Directory]) -> None:
+        if not self.journal:
+            return
+        self.journal.write_additions('directory', directories)
+
+    def revision_add(self, revisions: Iterable[Revision]) -> None:
+        if not self.journal:
+            return
+        self.journal.write_additions('revision', revisions)
+
+    def release_add(self, releases: Iterable[Release]) -> None:
+        if not self.journal:
+            return
+        self.journal.write_additions('release', releases)
+
+    def snapshot_add(
+            self, snapshots: Union[Iterable[Snapshot], Snapshot]) -> None:
+        if not self.journal:
+            return
+        snaps = snapshots if isinstance(snapshots, list) else [snapshots]
+        self.journal.write_additions('snapshot', snaps)
+
+    def origin_visit_add(self, visit: OriginVisit):
+        if not self.journal:
+            return
+        self.journal.write_addition('origin_visit', visit)
+
+    def origin_visit_update(self, visit: OriginVisit):
+        if not self.journal:
+            return
+        self.journal.write_update('origin_visit', visit)
+
+    def origin_visit_upsert(self, visits: Iterable[OriginVisit]):
+        if not self.journal:
+            return
+        self.journal.write_additions('origin_visit', visits)
+
+    def origin_add_one(self, origin: Origin):
+        if not self.journal:
+            return
+        self.journal.write_addition('origin', origin)