Search and SEO
What is Soft 404?
A soft 404 is a page that tells the user something is missing while returning HTTP 200 to the crawler. Search engines detect the mismatch and treat the URL as not found anyway — but the confusion wastes crawl attention and hides real problems.
Also called: soft not found
How they happen
- A "no results" page returning 200
- Mass redirects to the home page after a migration
- An empty category page that still renders a template
- A single-page application routing an unknown path to a generic view without changing the status
The correct behaviour
- Genuinely missing: return 404, with a helpful page
- Permanently gone and not coming back: return 410
- Moved: 301 to the specific equivalent
- Empty but valid: return 200 with genuinely useful content, or noindex it
Why it matters more on SPAs
A client-rendered application usually returns 200 for every path because routing happens in the browser. Without server-side handling, every typo becomes an indexable soft 404, which is one reason static generation is simpler to get right.
Where this is covered in depth
A definition can only go so far. Technical SEO, in the order the problems actually block you covers this properly — 4 minutes, free, no email required.
Who wrote this
Anas Bin Masud builds e-commerce sites and does technical SEO for businesses in the UK, Canada and Pakistan. These definitions come from client work rather than from a content brief — where an entry describes a mistake, it is usually one found on a real site. More about how I work.