What is a soft 404?

A soft 404 is a page that tells the visitor it is missing but tells the browser everything is fine, by returning a success status:

• The mismatch confuses indexing - search engines may keep the empty page in the index, or spend crawling on it.
• It usually comes from a friendly error page that was built as an ordinary page.
• The fix is the status code - a genuinely missing page should return 404, or 410 if it is gone for good.

Google Search Console reports soft 404s directly, which makes them one of the easier problems to find.