Google Says Use 503 During Short PHP Downtime

Google Search Central is reminding site owners to return a 503 status code when servers are temporarily offline for PHP patching. The guidance, reported by Search Engine Journal, is meant to signal that the outage is temporary so already indexed URLs can remain in Google Search.

The reminder was published the same day PHP released emergency fixes for two critical flaws that can allow attackers to run code without logging in. Google also warned site owners not to let downtime appear as a 404, a timeout, or a normal 200 page that only shows an error message.

What changed

Google Search Central said a 503, or Service Unavailable, is the right response during planned short-term downtime. It said indexed URLs are preserved while the site is unavailable, and normal behavior resumes after the site starts returning 200 responses again.

Google’s documentation also says 500, 503, and 429 responses can reduce crawler activity for a short period across the whole hostname. Site owners can also send a Retry-After header with a 503 or 429 to tell Google when to try again. At the same time, Google warns against keeping a 503 in place for more than one to two days, because URLs that keep returning it for multiple days may be dropped from the index.

What it means for your website

If your website runs on PHP and you need to take it offline briefly for security updates, the way your server responds matters for search visibility. A proper 503 tells Google the interruption is temporary. A 404, 500, timeout, or an error page served with a 200 can create the wrong signal.

There are limits. While a short 503 can protect indexed pages during maintenance, Google says slower crawling during that period means fewer new pages are discovered and existing pages are refreshed less often. Google also says its systems cannot refresh titles, descriptions, metadata, or structured data on a page that returns a 503. The robots.txt file should keep responding normally, because returning a 503 for robots.txt blocks all crawling.

What to do now

• If you expect short PHP maintenance, make sure the site returns an actual HTTP 503 during the outage, not a 404, timeout, 500, or a soft error page with a 200 status.
• Keep the downtime short. Google recommends not serving a 503 for longer than one to two days.
• If possible, add a Retry-After header so Google knows when to come back.
• Make sure robots.txt still responds normally during the outage, because a 503 on robots.txt blocks crawling.
• If a closure may last beyond a day or two, review Google’s longer-site-pause approach, which the report says can include an indexable home page that returns a 200 as a placeholder.