Which Top Sites Block Datacenter IPs — September 2026

This is the number that decides whether a scraper works. The same request, sent in the same second from a residential IP, went through on every one of those 52 hosts — so the refusal is about where the request came from, not what it asked for. The reverse happens too, and far less often: 17 sites refused the residential request while serving the datacenter one.

“Undisclosed” means the host announced no CDN in its response headers — not that it has none.

The full set is a free API: GET https://proxmint.com/api/site-blocks — add ?format=csv for a spreadsheet, ?blocked=all for every measured host. No key, CORS open, published CC BY 4.0.

1. Take the list. The Tranco daily top 1,000, re-fetched every run so the sample is reproducible.
2. Ask twice, at the same moment. A plain GET / from our own datacenter IP and the same request through a residential exit, following up to three redirects. Status and headers only — never the page body.
3. Confirm before counting. A refusal is re-asked before it counts: twice from the datacenter, where the IP never changes, and up to three times residentially, where every attempt draws a different exit.
4. Publish only the difference. A site counts as blocking datacenter IPs when the datacenter request was refused — 403, 429, a Cloudflare challenge, or no answer at all — and the residential request genuinely succeeded.
5. Exclude what we could not measure. 291 hosts where one leg never heard back from the origin at all. Most are infrastructure domains that Tranco ranks by DNS traffic and that serve no homepage to anyone — akamai.net, gtld-servers.net. A site that refuses both vantage points is not excluded: that is a measurement, and its answer is that it does not single out datacenter traffic.

On the user-agent: we identify ourselves honestly rather than impersonating a browser. We checked what that costs — across the top hosts, a browser user-agent and realistic Accept headers changed no status on either leg. The refusals we record are about the IP, not about how we introduce ourselves.

Data as of Sep 2, 2026, 11:02 PM UTC. · Companion measurement: how reliable free proxies actually are