diff --git a/requirements.txt b/requirements.txt
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,3 +5,4 @@
 vcversioner
 aiohttp
 tenacity
+typing_extensions
diff --git a/swh/storage/__init__.py b/swh/storage/__init__.py
--- a/swh/storage/__init__.py
+++ b/swh/storage/__init__.py
@@ -6,6 +6,7 @@
 import warnings
 
 from . import storage
+from .interface import StorageInterface
 
 Storage = storage.Storage
 
@@ -19,7 +20,7 @@
 }
 
 
-def get_storage(cls, **kwargs):
+def get_storage(cls, **kwargs) -> StorageInterface:
     """Get a storage object of class `storage_class` with arguments
     `storage_args`.
 
@@ -36,10 +37,6 @@
         ValueError if passed an unknown storage class.
 
     """
-    if cls not in STORAGE_IMPLEMENTATION:
-        raise ValueError('Unknown storage class `%s`. Supported: %s' % (
-            cls, ', '.join(STORAGE_IMPLEMENTATION)))
-
     if 'args' in kwargs:
         warnings.warn(
             'Explicit "args" key is deprecated, use keys directly instead.',
@@ -49,20 +46,27 @@
     if cls == 'pipeline':
         return get_storage_pipeline(**kwargs)
 
-    if cls == 'remote':
-        from .api.client import RemoteStorage as Storage
+    elif cls == 'remote':
+        from .api.client import RemoteStorage
+        return RemoteStorage(**kwargs)  # type: ignore # autogenerated methods
     elif cls == 'local':
         from .storage import Storage
+        return Storage(**kwargs)
     elif cls == 'memory':
-        from .in_memory import InMemoryStorage as Storage
+        from .in_memory import InMemoryStorage
+        return InMemoryStorage(**kwargs)
     elif cls == 'filter':
-        from .filter import FilteringProxyStorage as Storage
+        from .filter import FilteringProxyStorage
+        return FilteringProxyStorage(**kwargs)
     elif cls == 'buffer':
-        from .buffer import BufferingProxyStorage as Storage
+        from .buffer import BufferingProxyStorage
+        return BufferingProxyStorage(**kwargs)
     elif cls == 'retry':
-        from .retry import RetryingProxyStorage as Storage
-
-    return Storage(**kwargs)
+        from .retry import RetryingProxyStorage
+        return RetryingProxyStorage(**kwargs)
+    else:
+        raise ValueError('Unknown storage class `%s`. Supported: %s' % (
+            cls, ', '.join(STORAGE_IMPLEMENTATION)))
 
 
 def get_storage_pipeline(steps):
diff --git a/swh/storage/interface.py b/swh/storage/interface.py
--- a/swh/storage/interface.py
+++ b/swh/storage/interface.py
@@ -5,10 +5,12 @@
 
 from typing import Any, Dict, List, Optional
 
+from typing_extensions import Protocol
+
 from swh.core.api import remote_api_endpoint
 
 
-class StorageInterface:
+class StorageInterface(Protocol):
     @remote_api_endpoint('check_config')
     def check_config(self, *, check_write):
         """Check that the storage is configured and ready to go."""