When we talk about search engine optimization (SEO), most people think about keywords, backlinks, and content. But there’s another layer that quietly shapes your site’s visibility in search results: HTTP status codes.
These three-digit numbers are sent by your server to browsers and search engines every time someone requests a page. They tell crawlers whether your content is available, moved, or missing. For SEO, they can mean the difference between a well-indexed site and one that slowly fades from search results.
This guide will walk you through the most important status codes for SEO, explain what they mean, and show you how to use them properly.
Why HTTP Status Codes Matter for SEO
Search engines like Google use crawlers (bots) to discover and index web pages. When a crawler requests a page, the server responds with both the page content and an HTTP status code.
- A 200 OK means: “Here’s the content. Index it.”
- A 301 Moved Permanently says: “The content has moved here. Pass all SEO value to the new location.”
- A 404 Not Found tells the crawler: “Nothing here.”
Handled correctly, status codes help search engines understand your site’s structure. Misused, they can waste crawl budget, cause indexing errors, or dilute link equity.
Categories of HTTP Status Codes
Status codes are grouped by their first digit:
- 1xx – Informational: Rarely relevant for SEO.
- 2xx – Success: Request succeeded, page loads fine.
- 3xx – Redirection: Content has moved; tells bots where to go.
- 4xx – Client Error: Something is wrong with the request (e.g., page not found).
- 5xx – Server Error: Problem on the server’s end.
For SEO, the most important are 2xx, 3xx, 4xx, and 5xx.
Key Status Codes and Their SEO Impact
200 OK
This is the response you want for all indexable pages. It means the page exists, loads correctly, and can be crawled and ranked.
SEO tip: Make sure canonical pages (the main versions you want ranked) always return a 200.
301 Moved Permanently
A 301 tells search engines that a page has permanently moved to a new URL. Importantly, it transfers most of the SEO value (link equity) from the old page to the new one.
When to use:
- Migrating to a new domain
- Redirecting old URLs to updated versions
- Consolidating duplicate content
Mistake to avoid: Redirect chains (301 → 301 → 301). They slow down crawling and can weaken link equity. Always redirect old pages directly to the final destination.
302 Found (Temporary Redirect)
A 302 indicates that a page has moved temporarily, and search engines should keep the old URL indexed. Historically, 302s did not pass link equity, but Google now treats them more like 301s in many cases.
When to use:
- Seasonal promotions
- Temporary testing of new pages
SEO tip: Don’t use 302s for permanent changes—stick to 301s.
307 Temporary Redirect
Similar to 302, but stricter under HTTP/1.1. It explicitly means: “This redirect is temporary; request methods shouldn’t change.”
Use case: Rare for SEO, but helpful in APIs and technical setups where you need method consistency.
404 Not Found
A 404 tells crawlers that the page doesn’t exist. Google will eventually drop it from the index.
When to allow 404s:
- Content you’ve intentionally removed (e.g., discontinued products).
SEO tip: Don’t redirect all 404s to your homepage—it confuses crawlers and users. Instead, serve a custom 404 page with helpful navigation to keep visitors on your site.
410 Gone
A 410 status code is stronger than a 404. It tells search engines: “This page is permanently gone. Stop checking for it.” Google usually removes 410 pages from the index faster than 404s.
When to use:
- Deleted pages with no replacement
- Content removed for legal reasons.
500 Internal Server Error
A 500 signal that something is wrong on your server. If crawlers see a lot of these, they may slow down or stop indexing your site.
SEO tip: Monitor server logs and fix recurring 500 errors quickly.
503 Service Unavailable
A 503 means the server is temporarily unavailable, often used during maintenance. Unlike a 500, a 503 tells search engines: “Try again later.”
When to use:
- Planned downtime
- Rate-limiting crawlers
Best practice: Always include a Retry-After header so crawlers know when to return.
429 Too Many Requests
This code tells crawlers they are making too many requests in a short time. While it protects server resources, excessive 429s may prevent Google from indexing your pages efficiently.
SEO tip: Use crawl-delay rules or Google Search Console settings to control bot activity instead of relying solely on 429s.
Best Practices for Using Status Codes in SEO
- Always prefer 301s for permanent moves. They preserve SEO value.
- Avoid redirect chains and loops. Keep paths clean.
- Serve 404 or 410 for removed content. Don’t redirect everything to the homepage.
- Fix server errors quickly. Persistent 500s or 503s can harm rankings.
- Use custom 404 pages. They improve user experience and reduce bounce rates.
- Audit regularly. Use tools like Screaming Frog, Ahrefs, or Google Search Console to spot errors.
- Log monitoring. Check server logs to see how crawlers interact with your site.
Real-World Scenarios
- Site Migration: When moving from http://example.com to https://example.com, set up 301 redirects for every URL to its secure version. This preserves rankings.
- Product Out of Stock: If a product is temporarily unavailable, return a 200 with a note to users. If discontinued permanently, use 410.
- Seasonal Campaigns: Use 302 redirects for limited-time sales, so the original page regains priority after the campaign ends.
- Maintenance Window: Use 503 with a Retry-After header to tell crawlers to come back later.
Tools to Check Status Codes
- Browser extensions (Redirect Path, Ayima, Link Redirect Trace)
- Online checkers (httpstatus.io, Screaming Frog free tool)
- Command line (curl -I https://example.com/page)
- Search Console (Coverage and Crawl Stats reports)
Conclusion
HTTP status codes are more than just technical details—they’re signals that guide search engines in how to treat your content. By using the right codes in the right situations, you ensure that your site is crawled efficiently, indexed correctly, and ranked fairly.
- Use 200 OK for live pages.
- Use 301 for permanent redirects.
- Use 302/307 only for temporary moves.
- Let deleted content return 404 or 410.
- Avoid persistent 500/503 errors.
Mastering these signals helps you protect your site’s SEO health and ensures that both users and search engines have a smooth experience.