Which pages are giving my visitors server errors (500, 502, 504)?
Updated 2026-11-01
Short answer: server errors (the 5xx codes: 500, 502, 503, 504, and Cloudflare's 52x) often hit only some pages, some of the time. A slow page times out, one route crashes, a server behind the site goes down for a few minutes. You load the home page, it works, and you never see it. The record of every error is in your traffic data, not in your browser.
How to check it yourself
- If the site is on Cloudflare, open the domain in the Cloudflare dashboard, go to Analytics, and filter by status code 500 and above. Add the path to see which pages.
- Otherwise, read your host's access log and look for lines with a status of 500 or above.
- Note when they happen. Errors clustered at one time usually line up with a deploy, a traffic spike or a server restart.
What Preventionlabs shows
With a read-only Cloudflare token, a report reads Cloudflare's own request counts for the last 24 hours: how many server errors visitors got out of how many requests, which hours they happened in, each status code and what it means, and every address that returned one, with the count and the last time it happened. Preventionlabs' own test requests are left out of the counts. It also lists the most requested addresses that returned 404. Without a Cloudflare token, the report still loads the home page and up to 50 pages from the sitemap and shows which ones fail, but only at the moment it runs.
Price
Free to sign up, with 2 free reports on each domain. Then US$28 a month for 1,500 credits.