diff --git a/beat/web/algorithms/api.py b/beat/web/algorithms/api.py
index 1cae18b5a516255b0aaefc03e72036c2534f76b6..d85922e0fdee7fc3c9789e893e9baf02106eac24 100755
--- a/beat/web/algorithms/api.py
+++ b/beat/web/algorithms/api.py
@@ -182,7 +182,7 @@ def binary(request, author_name, object_name, version=None):
 
         file = request.FILES['binary']
 
-        binary_data = ''
+        binary_data = b''
         for chunk in file.chunks():
             binary_data += chunk