The Complete Guide to HTTP Status Codes & SEO
What Are HTTP Status Codes?
HTTP status codes are three-digit numbers sent by a web server in response to every request from a browser, search engine crawler, or any other HTTP client. They are defined by the Internet Engineering Task Force (IETF) in RFC 7231 and related specifications, and they form the backbone of how the web communicates success, failure, and redirection.
Every time Google, Bing, or any search engine crawls a URL on your website, the first thing they see is the HTTP status code. This code determines whether the page's content will be indexed, whether link equity (PageRank) flows through, and how the crawler allocates its limited crawl budget across your site.
The Five Status Code Classes
2xx — Success
The request was successfully received, understood, and accepted. 200 OK is the most common — it means the page loaded correctly and its content can be indexed. Other codes in this class include 201 Created (often used in APIs) and 204 No Content.
3xx — Redirection
The requested resource has moved. 301 Moved Permanently passes nearly full link equity and tells search engines to update their index. 302 Found is temporary — the original URL stays in the index. 307 and 308 are the modern equivalents that preserve the HTTP method during redirection.
4xx — Client Errors
The request contains an error on the client side. 404 Not Found means the page does not exist. 410 Gone means it was intentionally removed (processed faster than 404 by Google). 403 Forbidden means access is denied, and 429 Too Many Requests means rate limiting is active.
5xx — Server Errors
The server failed to fulfill a valid request. 500 Internal Server Error is a generic catch-all. 502 Bad Gateway and 503 Service Unavailable indicate infrastructure problems. Persistent 5xx errors can cause Google to reduce crawl rate and eventually deindex pages.
Network Errors (No Status Code)
Sometimes a request fails before receiving any HTTP response — DNS lookup failures, connection timeouts, SSL handshake errors, and connection resets all fall into this category. These are the most critical for SEO because the page is completely unreachable.
Why HTTP Status Codes Matter for SEO
Crawl Budget Impact
Google allocates a finite crawl budget to each website based on its authority and server health. Every URL that returns a 4xx or 5xx error wastes part of that budget — the crawler made a request, waited for a response, and got nothing useful in return. For large sites with thousands of pages, excessive error pages can prevent important new content from being discovered and indexed in a timely manner.
Link Equity (PageRank) Flow
When an external website links to one of your pages and that page returns a 404 error, the link equity is lost entirely. If the page was moved, a 301 redirect passes most of the accumulated PageRank to the new location. This is why monitoring status codes and maintaining proper redirects is essential — especially after site migrations, URL structure changes, or content consolidation.
User Experience Signals
Users who land on 404 error pages or encounter redirect loops have a terrible experience. They typically hit the back button and try a competitor's site instead. High bounce rates and low engagement from error pages send negative signals that indirectly impact your rankings. Google's quality raters explicitly look for broken pages and server errors as indicators of a poorly maintained website.
How Google Handles Different Status Codes
According to Google's documentation, Googlebot processes status codes as follows: 200 OK pages are crawled, rendered, and considered for indexing. 301 redirects cause the index to be updated to the new URL, passing link signals. 302/307 redirects keep the original URL in the index but follow the redirect to get content. 404/410 pages are eventually dropped from the index (410 is dropped faster). 5xx errors cause the crawler to slow down; persistent errors lead to deindexing.
Common HTTP Status Issues and Their Impact
404 Not Found Errors
The 404 status code is the most common error on the web. It occurs when a page has been deleted, renamed, or never existed at the requested URL. While a handful of 404 errors is normal and harmless, a large number — especially on pages with inbound links — represents significant lost opportunity. Google's John Mueller has confirmed that 404 errors on pages that legitimately do not exist are fine, but broken internal links to 404 pages should be fixed.
5xx Server Errors
Server errors are always more urgent than client errors. A 500 Internal Server Error indicates a bug in your application code, while 502 Bad Gateway and 503 Service Unavailable typically indicate infrastructure problems. If Googlebot encounters 5xx errors consistently, it will reduce crawl frequency for your entire site. In extreme cases, Google may temporarily drop your pages from search results entirely until the server recovers.
Redirect Loops
A redirect loop occurs when URL A redirects to URL B, which redirects back to URL A (either directly or through a longer chain). The browser or crawler gets stuck in an infinite cycle and eventually gives up with a "too many redirects" error. These are critical issues because the affected pages are completely inaccessible. Common causes include misconfigured HTTPS redirects, conflicting .htaccess rules, CDN redirect rules that conflict with origin server rules, and CMS plugins that create circular redirects.
Long Redirect Chains
A redirect chain occurs when the path from the original URL to the final destination involves multiple intermediate redirects: A → B → C → D. While Google follows up to 10 hops, each redirect adds latency (typically 50-200ms per hop) and risks losing a small amount of link equity at each step. Best practice is to have the original URL redirect directly to the final destination in a single hop.
302 vs 301 Redirect Misuse
A surprisingly common mistake is using 302 (temporary) redirects for permanent URL changes. When Google sees a 302, it keeps the original URL in its index and does not fully transfer link equity to the destination. Over time, Google may figure out the intent and treat it like a 301, but this is not guaranteed and wastes months of potential ranking benefit. Always use 301 for permanent changes and reserve 302 for genuinely temporary situations.
Soft 404 Errors
A soft 404 is a page that returns a 200 OK status code but displays content that says "page not found" or shows an empty/thin page. Google is sophisticated enough to detect many soft 404s and treats them as actual 404s in its index, but they waste crawl budget because the server claims the page is fine. Many CMS platforms create soft 404s by default when content is deleted — the URL still resolves but shows an error template with a 200 status code. The fix is to return a proper 404 or 410 status code.
How to Fix HTTP Status Issues
Fixing 404 Errors
- Identify 404 pages with inbound links or significant traffic in Google Search Console
- If the content moved to a new URL, implement a 301 redirect from the old URL to the new one
- If the content was deleted with no replacement, return a proper 404 or 410 status code
- Update internal links throughout your site to point to the correct URLs
- Create a custom 404 page that helps users navigate to relevant content
- Monitor for new 404 errors regularly using tools like this one
Fixing Server Errors (5xx)
- Check your server error logs for the root cause (application crashes, database connection failures, memory issues)
- For 502 Bad Gateway: verify your reverse proxy (Nginx, Apache) configuration and backend service health
- For 503 Service Unavailable: check if you've exceeded server resource limits or if maintenance mode is active
- Implement proper error monitoring (e.g., Sentry, Datadog) to catch 5xx errors in real time
- Set up uptime monitoring to be alerted immediately when server errors occur
Fixing Redirect Issues
- Redirect loops: Map out the complete redirect path, identify where the loop occurs, and update the conflicting rule
- Long chains: Replace multi-hop chains with a single redirect from source to final destination
- 302 → 301: Audit all 302 redirects; change permanent moves to 301
- Internal links to redirects: Update links to point to the final destination URL directly
Fixing Soft 404s
- Identify pages returning 200 OK but showing "not found" content
- Update your server or CMS to return a proper 404 status code for deleted content
- For dynamic routes, add server-side checks that return 404 when content does not exist
- Example in Next.js: use
notFound()fromnext/navigation
HTTP Status Code Best Practices
Regular Monitoring
HTTP status errors are not a one-time fix — they accumulate over time as content is updated, pages are reorganized, and links decay. Schedule regular audits (monthly for small sites, weekly for large sites) using tools like this HTTP Status Checker, Google Search Console's Coverage report, and server log analysis. Set up alerts for sudden spikes in 4xx or 5xx errors.
Custom 404 Page
Every website should have a well-designed custom 404 page that returns a proper 404 status code. The page should include a search bar, links to popular content, and a clear message explaining that the page was not found. Avoid automatically redirecting all 404s to the homepage — Google considers this a soft 404, and users find it confusing.
Redirect Strategy
Maintain a redirect map document that tracks all redirects on your site: source URL, destination URL, redirect type (301/302), and the reason for the redirect. During site migrations, create this map before the migration and test it thoroughly. Use redirect validation tools to verify that all redirects resolve correctly and that no chains or loops exist.
Use Google Search Console
Google Search Console's Pages (formerly Coverage) report shows exactly how Google sees your site's HTTP status codes. It categorizes pages into Indexed, Not Indexed, Error, and Warning states. Check the "Page indexing" section for "Not found (404)", "Server error (5xx)", "Redirect error", and "Soft 404" issues. This is the most authoritative source for understanding how Google is processing your URLs.
410 Gone for Intentional Removals
When you deliberately remove content and do not plan to bring it back, use a 410 Gone status code instead of 404. Google processes 410 pages faster than 404 pages, removing them from the index more quickly. This is especially useful after major content pruning exercises where you want Google to stop wasting crawl budget on deleted pages.