Email checker for UK lists
A UK list has two questions hanging over it. Will these addresses accept mail, and may you email them at all? ZapBounce answers the first one address by address. The second is PECR, and the result flags help you sort a list along the line that law draws between companies and individuals.
You can check a single address in the free email verifier, or upload a whole file on the bulk page. Developers call the same check from the API.
What PECR says about marketing email in the UK
The Information Commissioner's Office (ICO) enforces the Privacy and Electronic Communications Regulations, known as PECR. We read its electronic mail marketing guidance on 24 September 2026. It splits your list into two kinds of recipient, and each kind has its own rule.
Individuals need consent. You must not send them marketing email unless they have "specifically consented to electronic mail from you". The one exception is the soft opt-in: an existing customer who "bought (or negotiated to buy) a similar product or service from you in the past". That only holds if you offered a simple way to opt out when you took their details, and again in every message.
Corporate subscribers are different. The ICO says you can email "any corporate body (a company, Scottish partnership, limited liability partnership or government body)" without consent. It still advises keeping a do-not-email list of any business that objects or opts out. A suppression list is that list in practice.
Sole traders and some partnerships count as individuals, so the consent rule applies to them. Every message must also name who is sending it and give a valid address for opting out. The ICO marks this guidance as under review after recent changes to the law, so read its current page before a large send.
Mailbox providers on United Kingdom lists
- Gmail: gmail.com, plus googlemail.com, which you'll still see on older UK sign-ups from when Gmail ran as Google Mail in Britain.
- Outlook.com: hotmail.co.uk, live.co.uk and outlook.com, Microsoft's consumer mail service.
- Yahoo: yahoo.co.uk and ymail.com. Yahoo answers every mailbox probe with acceptance, so ZapBounce returns these rows as catch_all.
- Microsoft 365: company domains that run their mail on Microsoft's business service. Your list shows them under the company's own domain, not a Microsoft one.
- Broadband mail from UK internet providers, such as btinternet.com, sky.com, virginmedia.com and talktalk.net. ZapBounce runs the same MX lookup and SMTP handshake on these as on any other domain.
Split a UK B2B list along the PECR line
PECR lets you email a limited company without consent, but a sole trader needs it. No mail server tells you which one an address belongs to. What ZapBounce does give you is a set of flags on every result, and two of them map closely onto that line.
The free_provider flag marks addresses at consumer mailbox services such as gmail.com or hotmail.co.uk. On a UK business list, those are the rows most likely to belong to a sole trader or a small partnership. Pull them into their own segment and check your consent record before they get a campaign.
The role flag marks shared inboxes like info@ or sales@. At a limited company, a role inbox is a corporate address, which PECR's corporate rule covers. Read more on role-based email before you decide to keep or drop them.
How ZapBounce handles your data under UK GDPR
An email address identifies a person, so sending a list to any verifier is processing personal data. Under UK GDPR, Article 28(3) sets out what your contract with a processor must cover. That includes documented instructions, security, sub-processors and what happens at the end of the contract.
ZapBounce's data processing terms sit at /dpa and form part of the terms of service. A countersigned copy is available on request. Sub-processors are listed there by name: Vercel, Amazon Web Services, Cloudflare, Google and Stripe. Any change to that list is announced 30 days ahead.
ZapBounce is hosted in the United States. Your list never leaves that region except for the SMTP probe to the receiving mail server. Uploads and results are kept for 30 days by default, and each API key can set its own window from 0 to 90 days. You can delete a batch at once, or erase one address across the whole account.
ZapBounce never sells your addresses or adds them to a shared database. It doesn't contact the people on your list, and it doesn't reuse a list to improve the product. For the wider question, see whether email verification is GDPR compliant.
What a UK list costs to check
ZapBounce prices are the same for a UK list as for any other: $5 for 1,000 checks, $25 for 10,000 and $139 for 100,000. There's no minimum, and credits never expire. Every account also gets 100 free checks a month, with no card.
You pay for valid, invalid and catch_all results. Unknown results and duplicates are never billed. Gmail and Microsoft 365 block SMTP probes from cloud IP addresses for every verifier, and an unknown row on your UK file costs you nothing. Full tiers are on the pricing page.
Questions people ask
Is there a free email checker for UK addresses?
Yes. ZapBounce gives every account 100 free checks a month with no card, and the free email verifier checks one address at a time. UK domains such as hotmail.co.uk, yahoo.co.uk and btinternet.com go through the same MX lookup and SMTP handshake as any other.
Can I email UK business addresses without consent?
The ICO says you can email a corporate body, meaning a company, Scottish partnership, limited liability partnership or government body, without consent. Sole traders and some partnerships count as individuals and need consent or the soft opt-in. Every message must name the sender and give a way to opt out.
Does checking a UK email address send a message to it?
No. ZapBounce opens an SMTP connection to the receiving server, asks whether the mailbox exists, and closes the connection before the DATA step. No message is sent, and the person on the list never sees the check.
Why do yahoo.co.uk addresses come back as catch_all?
Yahoo accepts every mailbox probe to stop address harvesting, then bounces bad addresses later. ZapBounce runs one random-address probe at the domain, sees it accepted, and returns catch_all. It never guesses further, and the result is billed once.
Where is my UK list stored when ZapBounce checks it?
ZapBounce is hosted in the United States, and a list leaves that region only for the SMTP probe to the receiving mail server. Uploads and results are kept for 30 days by default, adjustable per API key from 0 to 90 days.
Check your list before the next send
100 free checks a month, no card. Unknown results are never billed, and credits never expire.