What this site keeps

Who runs it

Blockplain is a non-commercial hobby project, run from the UK. For the little described on this page, the person who runs it is the data controller. While the site is a draft, the contact below is the way to reach them.

What the site keeps

• No accounts, no sign-in, no email, and no database of searches.
• What you paste is used for the check you asked for, then dropped. It is not written to a file, a database or a log.
• The receipt is worked out in your browser from the result on the page. The site does not keep a copy and does not send the hash anywhere.
• No visitor analytics: the site does not count or follow visits.
• The “Technical detail” switch is not remembered. It resets when the page is reloaded.

Cookies

The site sets up to six cookies, one for each kind of check, only after you run that check. Each holds two numbers: how many checks this browser has run, and when the count started. They keep the free daily limits fair. They hold nothing you typed, and they expire after 24 hours.

• cs_firmfirm checks
• cs_cosearchcompany name searches
• cs_advertadvert checks
• cs_tokentoken checks
• cs_txtransactions explained
• cs_addraddresses explained

These cookies are strictly necessary for the limits to work, so the site does not ask first. Clearing them resets the count. There are no advertising or tracking cookies.

Where a check sends what you paste

To answer a check, the site's server asks the public source for that kind of record. The source sees a request from this site's server, not from your browser, so it does not see your internet address. Nothing is sold or shared with anyone else.

A firm's name or company number

Companies House, and the FCA Financial Services Register

A website's domain name

rdap.org, which passes the question to the registry for that domain's ending

A token's address

Sourcify, and when Sourcify has no source (or names an unverified implementation), the public node for the chain you chose

A transaction hash

The public node for the chain you chose

An address

The public node for the chain you chose, and, when the address has code, Sourcify

An advert's link

The advert's own website, which the server opens to read its words

Advert wording you paste is read on the site's server and sent nowhere else. Pastes travel in the body of the request, not in the page address. The latest-block page and the band across the top send nothing of yours: the server asks the public node of Ethereum, BNB Smart Chain, Base and Arbitrum One for the newest block, and asks blockstream.info for Bitcoin. Every visitor sees the same answer. The payment page also sends nothing of yours: the server asks Ethereum's public node for one payment the site keeps. The coin and exchange pages in Crypto also send nothing of yours: the server asks CoinGecko at most once every 24 hours for the fixed list's figures, and every visitor sees the same answer. A token address is also compared on this site's server with a saved copy of the UK Sanctions List, and so is an address on See it live. The copy's report date is 30 Oct 2026. The address is not sent to the FCDO.

The web host

• The site is hosted by Vercel. To serve a page, Vercel handles each request, including your internet address and browser, as any web host does.
• Vercel's request logs show the page address, the time and the browser for each request. Pastes are not in the page address, so they are not in those logs. On the plan this site uses, Vercel keeps the logs for one hour.
• Vercel is a US company and may handle requests in the United States. Its privacy notice says it complies with the UK Extension to the EU-U.S. Data Privacy Framework, and uses standard contractual clauses where the law requires.
• A posted check is also counted by internet address. After 30 from one address in 60 seconds, the host refuses the next ones until that minute has passed. The count is kept separately in each region.

• Vercel's privacy notice ↗ (updated 1 Jun 2026)
• Vercel runtime logs ↗ (updated 28 Aug 2026)
• Vercel WAF rate limiting ↗ (updated 28 Aug 2026)

Legal basis

Legitimate interests: to run the check you ask for, and to keep the site working and stop it being overused (the cookies, the host's logs, and the host's count of posted checks).

Your rights

Under UK GDPR you can ask to see, correct or delete personal data held about you, to restrict or object to its use, and to have a copy. The site keeps nothing you enter, so there is usually nothing to find, but you can still ask, and you will get an answer within one month. You can also complain to the Information Commissioner's Office.

Complain to the ICO ↗

Contact

For any privacy question, or to use your rights, email privacy@blockplain.uk.