HTTP Status Codes

What are HTTP status codes?

HTTP status codes are three-digit numbers that a web server sends back when it receives a request. They tell the browser or search crawler what happened. Did the page load? Did it move? Did something go wrong? The codes are grouped into five classes based on the first digit.^[1]

Understanding status codes helps content teams, IT teams, and compliance managers keep websites healthy.

What do the five status code classes mean?

1xx — Informational. The server received the request and is still working on it. These rarely appear in day-to-day website work. Example: 100 Continue.

2xx — Success. The request worked. The most common is 200 OK, which means the page loaded correctly. 204 No Content is used when a form is submitted but no page needs to load back.

3xx — Redirection. The content moved. The browser needs to follow a new URL.

• 301 Moved Permanently — The page has a new permanent home. Browsers and search engines update their records. Use this when changing URLs or migrating domains.
• 302 Found — The page is temporarily at a different URL. Search engines do not transfer full link value through 302s.
• 307 Temporary Redirect — Like 302, but keeps the original request method (GET or POST).
• 308 Permanent Redirect — Like 301, but keeps the original request method.^[1]

4xx — Client Error. Something went wrong with the request.

• 400 Bad Request — The request had bad formatting.
• 401 Unauthorized — Login is required.
• 403 Forbidden — The page exists but access is denied.
• 404 Not Found — The page does not exist. This is the most common broken link error.
• 410 Gone — The page was removed on purpose and will not come back. Search engines deindex 410 pages faster than 404 pages.

5xx — Server Error. The server itself had a problem.

• 500 Internal Server Error — A general server failure.
• 502 Bad Gateway — The server got an invalid response from another server.
• 503 Service Unavailable — The server is down for maintenance or overloaded.

Why do HTTP status codes matter for website management?

Content teams need to understand 301s and 404s. Every time a page URL changes, the right redirect must be in place. Without it, visitors and search engines hit dead ends.

IT teams monitor status codes to catch problems early. A sudden spike in 500 errors means something broke on the server. A growing list of 404s means content is being removed or restructured without proper redirects.

Legal and compliance teams care about status codes on required pages. If a mandatory privacy policy or accessibility statement returns a 404 or 503, the organization may be out of compliance until the page is restored.

How do status codes affect SEO?

Broken link detection. Site audits crawl every URL and flag pages returning 4xx or 5xx codes. These broken links hurt user experience and waste crawler attention.

Redirect management. Using a 302 (temporary) instead of a 301 (permanent) for a permanent URL change can prevent link equity from passing to the new page. Multiple consecutive redirects create a redirect chain that slows page load time. This directly affects search rankings.

Crawl efficiency. Search engines give each site a crawl budget. URLs returning errors waste that budget without adding any content to the index. A site with many errors may have new content crawled less often.^[2]

Uptime monitoring. Automated tools check status codes on a schedule. They catch pages that go offline before most visitors notice. Over time, unresolved 404s contribute to link rot across the site. For e-commerce sites processing thousands of orders daily, even a few minutes of 503 errors can mean lost revenue.

How Askem Helps

Continuous quality assurance tools detect 404s and other HTTP error codes across entire sites during scheduled scans. When a page starts returning an error code, these tools send an alert so IT and content teams can act quickly. Tools like Askem cover websites, portals, and PDFs without needing code installed on the monitored site. This is especially important for regulated organizations where required pages — such as privacy policies or accessibility statements — must always be reachable.

Sources

1. MDN Web Docs — HTTP response status codes: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status
2. Google Search Central — HTTP status codes that affect indexing: https://developers.google.com/search/docs/crawling-indexing/http-network-errors