What HTTP status code is most search-engine-friendly during a planned outage


If you have to take a site down for some type of unavoidable maintenance task (and it's not a big enough site that you have a backup server), what HTTP status code should you have your server return to minimize the possibility that search engines will think the site is gone?

I found this list of status codes from W3C, of which the following seem applicable:

  • 503 Service Unavailable
  • 500 Internal Server Error
  • 408 Timeout
  • 404 Not Found

I think 503 is the most appropriate, but I don't know what search engines might prefer.

Best Solution

From the horse's mouth:

If my site is down for maintenance, how can I tell Googlebot to come back later rather than to index the "down for maintenance" page?

You should configure your server to return a status of 503 (network unavailable) rather than 200 (successful). That lets Googlebot know to try the pages again later.