HTTP status codes

HTTP status codes are the three-digit numbers a server returns with every request, and they tell search engines exactly how to treat a URL. A page that returns 200 is live and indexable; a 301 has moved permanently; a 404 is gone. Getting these right is foundational technical SEO, because the wrong code sends crawlers the wrong signal about what to keep, drop, or follow.

The codes that matter for SEO

• 200 OK — the page is live; index it.
• 301 moved permanently — the URL moved; pass signals to the new one (see redirects).
• 302 found (temporary) — a temporary move; signals usually stay with the original.
• 404 not found / 410 gone — the page is missing; 410 states it is gone for good.
• 5xx server errors — the server failed; sustained 5xx responses erode crawl trust and can drop pages from the index.

Where it applies

Every request on every site, but audits pay off most where scale hides errors:

• Ecommerce — discontinued products should return 404/410 or 301 to a relevant page, not a soft 404.
• Migrations — the whole project hinges on correct 301s and clean 200s post-launch.
• Enterprise — thousands of stray 5xx or redirect chains quietly waste crawl budget.

What matters from each seat

• In-house — monitor status-code distributions over time; spikes in 404s or 5xx are early warnings.
• Engineering — return the truthful code; a “not found” page that returns 200 (a soft 404) confuses indexing.
• Agency and consulting — a crawl that buckets URLs by status code surfaces broken redirects and error clusters fast.