Google Search Central published a reminder on Wednesday that webmasters taking sites offline for emergency PHP patches should return a 503 status code. According to Search Engine Journal, this tells Google the Google server downtime is temporary and protects already indexed pages from disappearing during fixes for critical flaws.
Key takeaways
- Google issued a LinkedIn post on Wednesday advising sites to use HTTP 503 responses during server maintenance.
- John Mueller and Google documentation warn against using generic 404 or 200 error pages while offline.
- Serving a 503 status code for more than one to two days can cause URLs to drop from the Google index.
- Webmasters must ensure the 503 originates from a CDN or DNS rule rather than PHP itself, and keep robots.txt active.
What to do during Google server downtime?
When taking a site offline to apply urgent security patches, Google recommends serving an HTTP 503 Service Unavailable status code. Search Engine Journal reports that this method preserves indexed URLs in search results while work is underway. John Mueller suggested on Bluesky that teams can manage this response outside of PHP by pointing DNS elsewhere or using a content delivery network. He noted that letting responses time out or return 404 or 500 errors is a poor choice.
How HTTP status codes affect crawlers
Google's crawl rate documentation shows that 500, 503, and 429 responses temporarily reduce crawler traffic across an entire hostname. Webmasters can include a Retry-After HTTP header to specify when crawlers should try visiting the site again. However, if crawlers see these error codes on the same URL for multiple days, Google may drop the URL from its index. Also, Google systems cannot refresh metadata or structured data while a page returns a 503.
Why it matters
Website operators patching critical PHP vulnerabilities must act carefully because old versions like PHP 8.1 and older no longer receive regular official updates. Since the 503 response must come from a source that remains active while PHP is offline, administrators rely on CDNs or temporary servers. Keeping the robots.txt file accessible ensures crawling is not completely blocked, while respecting the strict one to two day limit prevents long-term search visibility loss.
Frequently asked questions
Google recommends serving an HTTP 503 Service Unavailable status code during temporary server outages and maintenance periods.
Google advises against serving a 503 status code for longer than one to two days because URLs may be dropped from the index.
Returning a 200 OK status code for an error page causes Google to index that error content, while generic 404s do not signal a temporary outage.
John Mueller noted that webmasters can generate the 503 response outside of PHP by pointing DNS elsewhere or using a CDN.
Google explicitly warns not to return a 503 status code for the robots.txt file because doing so blocks all crawling activity.
Based on reporting by Search Engine Journal. Read the original article
