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/HTTP Status Codes
📘Concept

HTTP Status Codes

최종 업데이트:

Definition

HTTP status codes are three-digit codes returned when a web server responds to requests from browsers or search engine bots. They communicate request processing results in a standardized way.

In SEO, status codes directly affect how crawl bots handle pages. 200 signals indexing eligibility, 301 transfers PageRank, and 404 signals index removal. Incorrect status codes cause crawl failures, indexing errors, and PageRank loss.

Summary

Core SEO status codes: ①200 (OK) = normal response, indexing target → ②301 = permanent move, PageRank transfer → ③302 = temporary move, PageRank uncertain → ④404 = page not found → ⑤410 = permanently deleted (faster index removal) → ⑥500/503 = server error, repeated issues reduce crawling. If 5xx errors repeat in GSC, inspect the server immediately.

Core SEO Status Codes

[COMPARISON_TABLE: HTTP status code SEO impact comparison]

2xx — Success

200 OK
The most common successful response. The server processed the request and returned content. Indexing-target pages must return 200.

204 No Content
The server processed the request but has no content to return. Normal for APIs, but if a web page returns 204, bots treat it as empty and indexing suffers.

3xx — Redirect

301 Moved Permanently
URL permanently moved. PageRank and backlink authority transfer to the new URL. Used for HTTPS migration, URL structure changes, and domain moves. See 301 Redirect for details.

302 Found (Temporary Redirect)
URL temporarily moved. PageRank transfer uncertain. Suitable for A/B tests and temporary maintenance pages. Using 302 for permanent moves can cause SEO loss.

307 Temporary Redirect
Similar to 302 but preserves HTTP method (POST, etc.).

308 Permanent Redirect
Similar to 301 but preserves HTTP method.

4xx — Client Error

404 Not Found
Requested URL does not exist on the server. When bots find 404, they remove the URL from crawl lists and the index. Natural response for deleted pages.

410 Gone
URL permanently deleted. Unlike 404, an explicit signal that it will not return. Google removes 410 pages from the index faster than 404. 410 is more SEO-friendly when permanently deleting content.

403 Forbidden
Server understood the request but denied access. Pages requiring authentication. Repeated 403 experiences may lower crawl trust for that site.

429 Too Many Requests
Bot sent too many requests and server rate-limited. Can be used for crawl rate control.

5xx — Server Error

500 Internal Server Error
Internal server error. Occasional incidents are not a major problem, but repeated occurrences cause Googlebot to reduce crawl frequency.

503 Service Unavailable
Server temporarily unavailable. Correct response during maintenance, but prolonged duration causes crawling problems. Retry-After header can tell bots when to retry.

Soft 404 Problem

A soft 404 occurs when a URL returns non-existent content while still returning HTTP 200.

Examples:

  • Product gone but page shows "This product is out of stock" with 200
  • Empty page for no search results returned as 200
  • Non-existent user profile returned as 200

When Google detects soft 404, it shows warnings in GSC and lowers crawl and indexing priority for that URL.

Fix: Return 404 or 410 for content that truly does not exist; use 301 redirect if permanently moved.

Monitoring Status Codes in GSC

Google Search Console → Indexing → Pages shows problems by status code. Especially:

  • 5xx errors: Server inspection needed immediately
  • 404 increase: Check for remaining internal/external links to deleted pages
  • Soft 404: Shown with "Crawled - currently not indexed" status

See Indexing Coverage and Google Search Console for details.

Korea Market Application

Korean Hosting and 5xx Errors

Shared hosting on Cafe24, Gabia, etc. often returns 503 errors when traffic concentrates. Repeated 503 causes Googlebot to reduce crawl frequency and delays indexing updates. Secure server resources in advance during traffic spikes from events and sales.

Naverbot and Status Codes

Naverbot (Yeti) also interprets HTTP status codes. 404 and 410 work as fast removal signals in the Naver index too. Check crawling errors in Naver Search Advisor → Webmaster Tools → Error report.

Out-of-Stock Product Handling in Ecommerce

Common situation in Korean ecommerce for out-of-stock/discontinued products:

  • Temporary out of stock: Keep 200 + restock notice (normal if shortage is temporary)
  • Permanent discontinuation: Return 410 or 301 to alternative product page
  • Seasonal products: Consider 302 redirect if returning next season

Frequently Asked Questions

Q. Should I use 404 or 410?
A. If content is permanently deleted with no plan to restore, 410 is more SEO-friendly. Google treats 410 as a clearer "permanently deleted" signal and removes it from the index faster. 404 is more suitable when the same URL may be restored later. In practice, many sites use only 404 without distinguishing, and the difference is often minor.

Q. Can I preserve PageRank from backlinks to deleted pages?
A. If deleted pages have backlinks, 301 redirect to a relevant replacement page is most effective. If no replacement exists, keep 404 or 410. Avoid redirecting everything to the homepage ("soft 404") — Google may penalize this.

Q. How serious is the SEO impact of 5xx errors?
A. Occasional 5xx errors (once or twice daily, recovered within minutes) have little impact. However, persistent 5xx errors (hours, repeated) can cause Googlebot to greatly reduce crawl frequency, delaying indexing updates by weeks or more. Repeated 5xx on large sites triggers GSC alerts.

Q. Googlebot sends too many 404 requests. What is wrong?
A. Main causes of many Googlebot 404 requests: ①Pages that existed but were deleted ②Wrong links from external sites (backlink typos) ③Deleted URLs still in sitemap ④Internal link typos. Check 404 error list in GSC, fix internal links, and update sitemap. Recover external backlink 404s with 301 redirects.

Q. Which status code should I use during server maintenance?
A. 503 Service Unavailable is the correct response. Set the Retry-After HTTP header to tell bots when to retry. 503 means temporary service interruption and should not last days. Schedule planned maintenance during low-traffic hours (early morning) and minimize duration.

Related Sources

  • MDN Web Docs (2024). HTTP response status codes. Mozilla Developer Network.
  • Google Search Central (2024). HTTP status codes. Google Developers.
  • Moz (2024). HTTP Status Codes. Moz Blog.

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