diff --git a/swh/core/config.py b/swh/core/config.py
--- a/swh/core/config.py
+++ b/swh/core/config.py
@@ -338,6 +338,8 @@
 
         if config_filename:
             config_filenames = [config_filename]
+        elif 'SWH_CONFIG_FILENAME' in os.environ:
+            config_filenames = [os.environ['SWH_CONFIG_FILENAME']]
         else:
             if not base_filename:
                 base_filename = cls.CONFIG_BASE_FILENAME