diff --git a/swh/objstorage/api/client.py b/swh/objstorage/api/client.py
--- a/swh/objstorage/api/client.py
+++ b/swh/objstorage/api/client.py
@@ -71,12 +71,7 @@
     # Streaming methods
 
     def add_stream(self, content_iter, obj_id, check_presence=True):
-        obj_id = hashutil.hash_to_hex(obj_id)
-        return self._proxy.post_stream(
-            "content/add_stream/{}".format(obj_id),
-            params={"check_presence": check_presence},
-            data=content_iter,
-        )
+        raise NotImplementedError
 
     def get_stream(self, obj_id, chunk_size=DEFAULT_CHUNK_SIZE):
         obj_id = hashutil.hash_to_hex(obj_id)
diff --git a/swh/objstorage/api/server.py b/swh/objstorage/api/server.py
--- a/swh/objstorage/api/server.py
+++ b/swh/objstorage/api/server.py
@@ -3,14 +3,12 @@
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
-import json
 import os
 
 import aiohttp.web
 
 from swh.core.api.asynchronous import RPCServerApp, decode_request
 from swh.core.api.asynchronous import encode_data_server as encode_data
-from swh.core.api.serializers import SWHJSONDecoder, msgpack_loads
 from swh.core.config import read as config_read
 from swh.core.statsd import statsd
 from swh.model import hashutil
@@ -105,39 +103,6 @@
 # Streaming methods
 
 
-@timed
-async def add_stream(request):
-    hex_id = request.match_info["hex_id"]
-    obj_id = hashutil.hash_to_bytes(hex_id)
-    check_pres = request.query.get("check_presence", "").lower() == "true"
-    objstorage = request.app["objstorage"]
-
-    if check_pres and obj_id in objstorage:
-        return encode_data(obj_id)
-
-    # XXX this really should go in a decode_stream_request coroutine in
-    # swh.core, but since py35 does not support async generators, it cannot
-    # easily be made for now
-    content_type = request.headers.get("Content-Type")
-    if content_type == "application/x-msgpack":
-        decode = msgpack_loads
-    elif content_type == "application/json":
-        decode = lambda x: json.loads(x, cls=SWHJSONDecoder)  # noqa
-    else:
-        raise ValueError("Wrong content type `%s` for API request" % content_type)
-
-    buffer = b""
-    with objstorage.chunk_writer(obj_id) as write:
-        while not request.content.at_eof():
-            data, eot = await request.content.readchunk()
-            buffer += data
-            if eot:
-                write(decode(buffer))
-                buffer = b""
-
-    return encode_data(obj_id)
-
-
 @timed
 async def get_stream(request):
     hex_id = request.match_info["hex_id"]
@@ -188,7 +153,6 @@
     app.router.add_route("POST", "/content/check", check)
     app.router.add_route("POST", "/content/delete", delete)
     app.router.add_route("GET", "/content", list_content)
-    app.router.add_route("POST", "/content/add_stream/{hex_id}", add_stream)
     app.router.add_route("GET", "/content/get_stream/{hex_id}", get_stream)
     return app
 
diff --git a/swh/objstorage/backends/pathslicing.py b/swh/objstorage/backends/pathslicing.py
--- a/swh/objstorage/backends/pathslicing.py
+++ b/swh/objstorage/backends/pathslicing.py
@@ -335,6 +335,22 @@
             f.write(compressor.flush())
 
     def add_stream(self, content_iter, obj_id, check_presence=True):
+        """Add a new object to the object storage using streaming.
+
+        This function is identical to add() except it takes a generator that
+        yields the chunked content instead of the whole content at once.
+
+        Args:
+            content (bytes): chunked generator that yields the object's raw
+                content to add in storage.
+            obj_id (bytes): object identifier
+            check_presence (bool): indicate if the presence of the
+                content should be verified before adding the file.
+
+        Returns:
+            the id (bytes) of the object into the storage.
+
+        """
         if check_presence and obj_id in self:
             return obj_id
 
diff --git a/swh/objstorage/backends/seaweedfs/http.py b/swh/objstorage/backends/seaweedfs/http.py
--- a/swh/objstorage/backends/seaweedfs/http.py
+++ b/swh/objstorage/backends/seaweedfs/http.py
@@ -95,7 +95,5 @@
                 params["lastFileName"] = dircontent["LastFileName"]
 
             else:
-                LOGGER.error(
-                    'Error listing "%s". [HTTP %d]', self.url, rsp.status_code
-                )
+                LOGGER.error('Error listing "%s". [HTTP %d]', self.url, rsp.status_code)
                 break