Naven
Glossary
Soft 404
A page that says "not found" while returning a success status.
The classic case is a single-page app serving its shell for every URL, so a mistyped address returns 200 with the homepage. Search engines detect it, report it, and decline to index — and every junk URL a crawler invents spends crawl budget the site could have spent elsewhere.
The fix is for the server to know which paths are real.
Where Naven stands
Naven's Worker checks the path against its eight real routes and returns a genuine 404 for everything else.