diff --git a/swh/counters/journal_client.py b/swh/counters/journal_client.py
index 07e0488..66942b4 100644
--- a/swh/counters/journal_client.py
+++ b/swh/counters/journal_client.py
@@ -1,52 +1,52 @@
 # Copyright (C) 2021  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 Dict
 
 import msgpack
 
-from swh.counters.redis import Redis
+from swh.counters.interface import CountersInterface
 
 
 def process_journal_messages(
-    messages: Dict[str, Dict[bytes, bytes]], *, counters: Redis
+    messages: Dict[str, Dict[bytes, bytes]], *, counters: CountersInterface
 ) -> None:
     """Count the number of different values of an object's property.
        It allow for example to count the persons inside the
        Release (authors) and Revision (authors and committers) classes
     """
     for key in messages.keys():
         counters.add(key, messages[key])
 
     if "revision" in messages:
         process_revisions(messages["revision"], counters)
 
     if "release" in messages:
         process_releases(messages["release"], counters)
 
 
-def process_revisions(revisions: Dict[bytes, bytes], counters: Redis):
+def process_revisions(revisions: Dict[bytes, bytes], counters: CountersInterface):
     """Count the number of different authors and committers on the
        revisions (in the person collection)"""
     persons = set()
     for revision_bytes in revisions.values():
         revision = msgpack.loads(revision_bytes)
         persons.add(revision["author"]["fullname"])
         persons.add(revision["committer"]["fullname"])
 
     counters.add("person", list(persons))
 
 
-def process_releases(releases: Dict[bytes, bytes], counters: Redis):
+def process_releases(releases: Dict[bytes, bytes], counters: CountersInterface):
     """Count the number of different authors on the
        releases (in the person collection)"""
     persons = set()
     for release_bytes in releases.values():
         release = msgpack.loads(release_bytes)
         author = release.get("author")
         if author and "fullname" in author:
             persons.add(author["fullname"])
 
     counters.add("person", list(persons))