5xx server errors are HTTP status codes from 500 to 599. They tell the client that a request was valid but the server failed to fulfill it. Codes in the 4xx range, by contrast, point to a problem with the request itself.
At a glance
- Status code
- 500 to 599
- Class
- 5xx (server error)
- Duration
- not defined, 503 stands for a temporary outage according to the RFC
- In Google
- crawling slows down temporarily, response content is ignored, URLs with a persistent error drop out of the index
- Specification
- RFC 9110, section 15.6
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Which 5xx codes matter most?
- 500 Internal Server Error is the generic failure, often an application bug or misconfiguration.
- 502 Bad Gateway means a proxy received an invalid response from an upstream server.
- 503 Service Unavailable means the server is temporarily not ready, for example during maintenance or overload.
- 504 Gateway Timeout means a proxy received no timely response from upstream.
Common causes listed by practice guides are code errors, failed deployments, exhausted CPU, memory or connections, CDN or proxy misconfiguration and unhealthy upstream services.
| Status code | Meaning per RFC | How Googlebot reacts | Effect on the index | Retry-After |
|---|---|---|---|---|
| 429 Too Many Requests | too many requests in a given amount of time (rate limiting, RFC 6585) | treated as a sign of an overloaded server and as a server error; crawling temporarily slows down | indexed URLs are kept for now; if Googlebot sees the code on the same URL for multiple days, it may be dropped | RFC: may be included; Google: tells crawlers when they can retry |
| 500 Internal Server Error | unexpected condition on the server | the site's crawl rate drops in proportion to the number of URLs returning a server error | indexed URLs are kept for now; persistent errors get them removed, possibly after multiple days on the same URL | Google only describes it for 503 and 429 |
| 502 Bad Gateway | a gateway or proxy got an invalid response from the server behind it | same as 500 | indexed URLs are kept for now and removed if the error persists | Google only describes it for 503 and 429 |
| 503 Service Unavailable | temporarily unavailable, for example due to overload or maintenance | same as 500 | indexed URLs are kept for now; if Googlebot sees the code on the same URL for multiple days, it may be dropped | RFC: may be included and states the expected downtime; Google: tells crawlers when they can retry (seconds or a date) |
| 504 Gateway Timeout | a gateway or proxy didn't get a timely response from the server behind it | not listed individually by Google; for all 5xx codes, crawling temporarily slows down | indexed URLs are kept for now but eventually dropped (statement for all 5xx) | Google only describes it for 503 and 429 |
Google ignores any content it receives with a 5xx response. Once the server responds with 2xx again, Google gradually increases the crawl rate. To deliberately reduce crawling for a short time (a few hours up to 1-2 days), Google names 500, 503 or 429 and advises against doing so for longer. Google treats network timeouts, connection resets and DNS errors similarly to 5xx errors; according to Google, unreachable URLs are removed from the index within days. Sources: Google Crawling Infrastructure: How HTTP status codes affect Google's crawlers (last updated 2026-02-04); Google Crawling Infrastructure: Reduce the Google crawl rate (last updated 2026-10-06); Google Crawling Infrastructure: Debug network and DNS errors (last updated 2025-12-18); RFC 9110: HTTP Semantics, 15.6 Server Error 5xx and 10.2.3 Retry-After; RFC 6585: Additional HTTP Status Codes, 4. 429 Too Many Requests. Last checked: .
How does Google handle 5xx errors?
Google states that 5xx errors, like 429, make its crawlers slow down temporarily and that Google lowers the crawl rate for the site. URLs that persistently return a server error are removed from the index. The status code documentation names no time frame. Google’s guidance on reducing the crawl rate says a URL may be dropped from the index if it returns 500, 503 or 429 for multiple days.
Search Console generates error messages for status codes in the 4xx to 5xx range.
Example
HTTP/1.1 500 Internal Server Error
Content-Type: text/html
<h1>Something went wrong</h1>
Common mistakes
- A maintenance page that returns 200. For a short outage, Google’s documentation on temporarily pausing a website names a 503 response.
- Using 5xx as a throttle for too long. Google advises against returning 500, 503 or 429 for longer than one to two days. If Googlebot sees the status on the same URL for multiple days, the URL may be dropped from the index.
- Watching only status codes. Google treats network timeouts, connection resets and DNS errors similarly to 5xx errors. According to the documentation, indexed URLs that stay unreachable are removed from the index within days.
Frequently asked questions
What is the difference between 4xx and 5xx errors? 4xx codes indicate a problem with the request, such as a missing page. 5xx codes indicate that the server failed. Google reads 429 (a 4xx code) as a server overload signal.
Sources
- How HTTP status codes affect Google's crawlers – Google Crawling Infrastructuredevelopers.google.com
- HTTP response status codes – MDN Web Docsdeveloper.mozilla.org
- 5xx Server Errors: How to Find and Fix for SEO – Lumar (secondary)lumar.io
- Reduce the Google crawl rate – Google Crawling Infrastructuredevelopers.google.com
- Temporarily pause or disable a website – Google Search Centraldevelopers.google.com
- DNS and network errors and Google Search – Google Crawling Infrastructuredevelopers.google.com
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