diff --git a/app/config.py b/app/config.py
index 4662c5d..c98a11d 100644
--- a/app/config.py
+++ b/app/config.py
@@ -54,6 +54,10 @@ class Config:
     # Keep only the newest N archives after a backup made from the web UI.
     # Set to 0 to keep everything.
     BACKUP_KEEP = int(os.environ.get('BACKUP_KEEP', 5))
+    # Ceiling for archives uploaded through the admin page, in bytes.
+    # 0 = no limit. This is separate from MAX_CONTENT_LENGTH: backup uploads
+    # stream straight to disk and never go through Flask's form parser.
+    BACKUP_MAX_UPLOAD = int(os.environ.get('BACKUP_MAX_UPLOAD', 0))
 
     # Pagination
     SETS_PER_PAGE = int(os.environ.get('SETS_PER_PAGE', 20))