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
@@ -1,11 +1,12 @@
-# Copyright (C) 2015-2020  The Software Heritage developers
+# Copyright (C) 2015-2021  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
 
+import contextlib
 from typing import Any, Dict, Iterable, Union
 
-from swh.core.api import RemoteException, RPCClient
+from swh.core.api import AsyncRPCClient, BaseRPCClient, RemoteException, RPCClient
 from swh.model.model import Content
 
 from ..exc import HashCollision, StorageAPIError, StorageArgumentException
@@ -13,8 +14,8 @@
 from .serializers import DECODERS, ENCODERS
 
 
-class RemoteStorage(RPCClient):
-    """Proxy to a remote storage API"""
+class BaseRemoteStorage(BaseRPCClient):
+    """Base class for :class:`RemoteStorage` and :class:`AsyncRemoteStorage`."""
 
     api_exception = StorageAPIError
     backend_class = StorageInterface
@@ -24,13 +25,13 @@
     extra_type_decoders = DECODERS
     extra_type_encoders = ENCODERS
 
-    def raise_for_status(self, response) -> None:
+    def raise_for_status(self, response):
         try:
             super().raise_for_status(response)
         except RemoteException as e:
             if (
                 e.response is not None
-                and e.response.status_code == 500
+                and self._get_status_code(e.response) == 500
                 and e.args
                 and e.args[0].get("type") == "HashCollision"
             ):
@@ -40,10 +41,6 @@
             else:
                 raise
 
-    def content_add(self, content: Iterable[Union[Content, Dict[str, Any]]]):
-        content = [c.with_data() if isinstance(c, Content) else c for c in content]
-        return self.post("content/add", {"content": content})
-
     def reset(self):
         return self.post("reset", {})
 
@@ -52,3 +49,23 @@
 
     def refresh_stat_counters(self):
         return self.get("stat/refresh")
+
+
+class RemoteStorage(BaseRemoteStorage, RPCClient):
+    """Sync proxy to a remote storage API"""
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.async_storage = lambda: AsyncRemoteStorage(*args, **kwargs)
+
+    def content_add(self, content: Iterable[Union[Content, Dict[str, Any]]]):
+        content = [c.with_data() if isinstance(c, Content) else c for c in content]
+        return self.post("content/add", {"content": content})
+
+
+class AsyncRemoteStorage(BaseRemoteStorage, AsyncRPCClient):
+    """Async proxy to a remote storage API"""
+
+    async def content_add(self, content: Iterable[Union[Content, Dict[str, Any]]]):
+        content = [c.with_data() if isinstance(c, Content) else c for c in content]
+        return await self.post("content/add", {"content": content})