diff --git a/app/site_files.rb b/app/site_files.rb
index 9ba69267..3dd9132c 100644
--- a/app/site_files.rb
+++ b/app/site_files.rb
@@ -231,6 +231,7 @@ end
 post '/site_files/chat' do
   require_login
   dont_browser_cache
+  headers 'X-Accel-Buffering' => 'no'
   halt(403) unless parent_site.supporter?
 
   # Ensure the request is treated as a stream