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
@@ -300,7 +300,10 @@
 @encode
 @process_metrics
 def snapshot_add():
-    return get_storage().snapshot_add(**decode_request(request))
+    req_data = decode_request(request)
+    if 'snapshot' in req_data:
+        req_data['snapshots'] = req_data.pop('snapshot')
+    return get_storage().snapshot_add(**req_data)
 
 
 @app.route('/snapshot', methods=['POST'])