# Who is hosting this website? Hosting checker with an EU check

> Enter a domain to see which company hosts it, who owns that company, where its network is registered, and whether the site passes an EU data check.

Facts checked 2026-10-17.

*Enter a domain to see which company hosts it, who owns that company, where its network is registered, and whether the site passes an EU data check. The tool runs on the web page: https://ployz.dev/tools/who-hosts*

## How the checker finds the host

It reads two public records. DNS gives the site's addresses, and when the domain is a CNAME, the name of the platform it points at. The regional internet registry that hands out the address gives each address's network name, the company it's registered to and, usually, a country. The checker knows the networks and CNAMEs of 17 platforms and providers, from Vercel and Cloudflare to Hetzner and OVHcloud, and names the company that owns each one. Hetzner and OVHcloud register some IPv6 blocks under their customers' names, so an address inside their own registered ranges counts as theirs.

A CNAME wins over the address, because it's the more specific answer. A site whose DNS points at netlify.app is on Netlify, even though the address belongs to Amazon. A site that points straight at an Amazon address could be on Amazon, Netlify or Heroku, and the checker says it can't tell which.

A CDN hides the host. Cloudflare and Amazon's CloudFront answer with their own addresses and fetch pages from the real server out of view, so for a site behind them the checker names the CDN and stops there.

## What the EU check means

Data residency is where data is stored. Cloud sovereignty is whose laws can reach it. The EU check asks both questions about the networks the site runs on, and it passes only when both answers are the EU.

It checks the first IPv4 and the first IPv6 address the domain resolves to. It fails when the platform, or the company that owns either network, is American, because the US CLOUD Act lets US authorities demand data a US company controls, wherever the server is. A Vercel site on a Frankfurt server fails for that reason, and so does a site behind Cloudflare. With no American company found, it says unknown, not pass, when a CDN hides the server, the registry lists no country, the registry doesn't answer, or the DNS lookup for IPv4 or IPv6 fails. It fails when either network is registered outside the EU, and says unknown when the network is in the EU but belongs to a company this checker doesn't know.

A pass doesn't put a site beyond US law. A company based outside the US can still fall under US jurisdiction if it does enough business in the US, and US courts decide that case by case.

The country is where the address block is registered, which is usually but not always where the server is. A provider can register a block in one country and route it to a data center in another. Treat a pass as a strong sign, and check the provider's own data center list before you promise a client where their data lives.

## When the host is a platform

For a site on Vercel, Netlify, Heroku, Fly.io, Railway or Render, the checker shows what a small app costs on that platform next to the same app on one Hetzner server. The numbers come from this site's pricing articles, which show the full bill and the prices they're based on.

Ployz runs your apps on servers you rent yourself, from Hetzner, OVHcloud, Scaleway or any provider, so you choose the country and the company the data sits with. One app can span several servers. See [how Ployz runs one app across several servers](https://ployz.dev/features/multiple-servers).

## Questions

### How do I find out who is hosting a website?

Look up the domain's address in DNS, then ask the regional internet registry who holds that address block. The checker does both. When the domain is a CNAME for a platform such as Vercel, Netlify or Render, the CNAME names the platform before the address does.

### Why does a Netlify site show up as Amazon?

Netlify's and Heroku's addresses belong to Amazon, so the registry names Amazon. When the site's DNS is a CNAME to netlify.app or herokuapp.com, the checker names the platform. When it points straight at an address, the address alone can't tell Netlify, Heroku and Amazon apart, and the checker says so.

### Why can't it see the server behind Cloudflare?

Cloudflare answers for the site with its own addresses and fetches pages from the real server out of view. The checker only sees Cloudflare, so it names Cloudflare and says the server behind it can't be seen from outside.

### What is the difference between data residency and cloud sovereignty?

Data residency is where data is stored. Cloud sovereignty is whose laws can reach it. A server in Frankfurt run by a US company has EU data residency, but the US CLOUD Act lets US authorities demand the data from that company, so the checker fails it.

### Does passing the EU check make a site GDPR compliant?

No. The check reads the network and the company that owns it, not how the site handles personal data. GDPR compliance depends on what the site collects, why, and who it shares the data with. The check answers one narrower question, whether the server sits on an EU network owned by a company based outside the US.

### Where does the domain I enter go?

Your browser sends the domain to Cloudflare's public DNS over HTTPS, or to Google's if Cloudflare doesn't answer. It sends the first IPv4 and the first IPv6 address the domain points at to rdap.org, which redirects your browser to the registry for that address. Ployz's server never receives either.

## Sources

- [Cloudflare: DNS over HTTPS, JSON format](https://developers.cloudflare.com/1.1.1.1/encryption/dns-over-https/make-api-requests/dns-json/)
- [Google Public DNS: JSON API](https://developers.google.com/speed/public-dns/docs/doh/json)
- [rdap.org](https://about.rdap.org/)
- [RFC 9083: RDAP responses](https://www.rfc-editor.org/rfc/rfc9083)
- [US Department of Justice: CLOUD Act resources](https://www.justice.gov/criminal/cloud-act-resources)
- [US Department of Justice: CLOUD Act FAQ, questions 24 and 25](https://www.justice.gov/criminal/media/999616/dl?inline)
- [European Union: member countries](https://european-union.europa.eu/principles-countries-history/eu-countries_en)
- [Vercel: terms of service](https://vercel.com/legal/terms)
- [SEC EDGAR: Vercel Inc.](https://data.sec.gov/submissions/CIK0001893137.json)
- [Netlify: terms of use](https://www.netlify.com/legal/terms-of-use/)
- [Netlify: subprocessors, naming Amazon Web Services as its cloud infrastructure provider](https://www.netlify.com/trust-center/?itemUid=e3fae2ca-94a9-416b-b577-5c90e382df57)
- [SEC EDGAR: Netlify, Inc.](https://data.sec.gov/submissions/CIK0001672598.json)
- [Heroku: security, hosted in Amazon's data centers](https://www.heroku.com/policy/security/)
- [Salesforce: subsidiaries, including Heroku](https://www.sec.gov/Archives/edgar/data/1108524/000110852426000060/ex211listofsubsidiariesfy26.htm)
- [SEC EDGAR: Salesforce, Inc.](https://data.sec.gov/submissions/CIK0001108524.json)
- [Fly.io: terms of service](https://fly.io/legal/terms-of-service)
- [SEC EDGAR: Fly.io, Inc.](https://data.sec.gov/submissions/CIK0002144091.json)
- [Railway: data processing addendum](https://railway.com/legal/dpa)
- [Railway: terms of service](https://railway.com/legal/terms)
- [Render: terms of service](https://render.com/terms)
- [SEC EDGAR: Render Services, Inc.](https://data.sec.gov/submissions/CIK0001836313.json)
- [Cloudflare: website terms](https://www.cloudflare.com/website-terms/)
- [SEC EDGAR: Cloudflare, Inc.](https://data.sec.gov/submissions/CIK0001477333.json)
- [Amazon: subsidiaries](https://www.sec.gov/Archives/edgar/data/1018724/000101872426000004/amzn-20251231xex211.htm)
- [SEC EDGAR: Amazon.com, Inc.](https://data.sec.gov/submissions/CIK0001018724.json)
- [Alphabet: subsidiaries, including Google LLC](https://www.sec.gov/Archives/edgar/data/1652044/000165204426000018/googexhibit2101q42025.htm)
- [SEC EDGAR: Alphabet Inc.](https://data.sec.gov/submissions/CIK0001652044.json)
- [Microsoft: subsidiaries](https://www.sec.gov/Archives/edgar/data/789019/000119312526323660/msft-ex21.htm)
- [SEC EDGAR: Microsoft Corporation](https://data.sec.gov/submissions/CIK0000789019.json)
- [Hetzner: legal notice](https://www.hetzner.com/legal/legal-notice/)
- [OVHcloud: terms and conditions](https://www.ovhcloud.com/en/terms-and-conditions/)
- [French company register: OVH Groupe](https://recherche-entreprises.api.gouv.fr/search?q=537407926)
- [OVHcloud US: terms of service, with OVH US LLC](https://us.ovhcloud.com/legal/terms-of-service/)
- [Scaleway: about us](https://www.scaleway.com/en/about-us/)
- [French company register: iliad](https://recherche-entreprises.api.gouv.fr/search?q=342376332)
- [DigitalOcean Holdings: subsidiaries, including DigitalOcean, LLC](https://www.sec.gov/Archives/edgar/data/1582961/000158296126000019/exhibit211-2025xq4.htm)
- [SEC EDGAR: DigitalOcean Holdings, Inc.](https://data.sec.gov/submissions/CIK0001582961.json)
- [Akamai: annual report, on the Linode acquisition](https://www.sec.gov/Archives/edgar/data/1086222/000108622226000022/akam-20251231.htm)
- [SEC EDGAR: Akamai Technologies, Inc.](https://data.sec.gov/submissions/CIK0001086222.json)
- [Vultr: terms of service, with The Constant Company, LLC](https://www.vultr.com/legal/tos/)
- [PeeringDB: The Constant Company, LLC, West Palm Beach, US](https://www.peeringdb.com/org/1051)
- [Vercel pricing, with the small-app bill](https://ployz.dev/blog/vercel-pricing)
- [Netlify pricing, with the small-app bill](https://ployz.dev/blog/netlify-pricing)
- [Heroku pricing, with the small-app bill](https://ployz.dev/blog/heroku-pricing)
- [Fly.io pricing, with the small-app bill](https://ployz.dev/blog/fly-io-pricing)
- [Railway pricing, with the small-app bill](https://ployz.dev/blog/railway-pricing)
- [Render pricing, with the small-app bill](https://ployz.dev/blog/render-pricing)

[Run your app on multiple servers without Kubernetes](https://ployz.dev/features/multiple-servers)