diff --git a/swh/storage/api/client.py b/swh/storage/api/client.py
--- a/swh/storage/api/client.py
+++ b/swh/storage/api/client.py
@@ -17,6 +17,9 @@
     def check_config(self, *, check_write):
         return self.post('check_config', {'check_write': check_write})
 
+    def reset(self):
+        return self.post('reset', {})
+
     def content_add(self, content):
         return self.post('content/add', {'content': content})
 
diff --git a/swh/storage/api/server.py b/swh/storage/api/server.py
--- a/swh/storage/api/server.py
+++ b/swh/storage/api/server.py
@@ -135,6 +135,12 @@
     return encode_data(get_storage().check_config(**decode_request(request)))
 
 
+@app.route('/reset', methods=['POST'])
+@timed
+def reset():
+    return encode_data(get_storage().reset(**decode_request(request)))
+
+
 @app.route('/content/missing', methods=['POST'])
 @timed
 def content_missing():
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
@@ -34,6 +34,14 @@
         self._contents = {}
         self._content_indexes = defaultdict(lambda: defaultdict(set))
 
+        self.reset()
+
+        if journal_writer:
+            self.journal_writer = get_journal_writer(**journal_writer)
+        else:
+            self.journal_writer = None
+
+    def reset(self):
         self._directories = {}
         self._revisions = {}
         self._releases = {}
@@ -50,10 +58,6 @@
         self._sorted_sha1s = []
 
         self.objstorage = get_objstorage('memory', {})
-        if journal_writer:
-            self.journal_writer = get_journal_writer(**journal_writer)
-        else:
-            self.journal_writer = None
 
     def check_config(self, *, check_write):
         """Check that the storage is configured and ready to go."""