It’s a free bulk email checker: paste the whole list and every address is validated at once, with no sign-up and no upload. Use it to clean an email list before a newsletter, a campaign or an import into a new email service.
In the first example, Gmial.com and .con are fixed; the Mailinator address (throwaway), the second Amy (duplicate), dan@@example.org (two @ signs), the no-reply address and Eve’s second address (the same Gmail inbox) are removed. The list above the box shows each of those with its reason.
What it checks
- Typos in big providers:
gmial.com,hotmial.com,yaho.com,outlok.comand others become the right domain, and endings like.conor.cmobecome.com. Each fix is listed so you can check it. - Addresses that can’t work: no @ or two of them, spaces or commas inside, two dots in a row, nothing before or after the @, or an ending that doesn’t exist, like
.coom(checked against the official list of domain endings). - Duplicates: it removes duplicate emails whatever the capitals. Gmail ignores dots and anything after a plus, so
j.smith+news@gmail.comandjsmith@gmail.comreach the same inbox and count as one. - Throwaway addresses from more than 9,000 disposable email services such as Mailinator, YOPmail and 10 Minute Mail. People use them to get past a sign-up form; nobody reads them a day later.
- No-reply addresses like
noreply@,do-not-reply@andmailer-daemon@. - Shared inboxes like
info@,sales@andsupport@, if you tick that box. They’re real addresses, often the only contact you have for a business, so they’re kept unless you ask. - Domains that can’t receive email, if you tick Check online: each domain’s mail servers are looked up, and addresses are removed when the domain doesn’t exist, has no mail server, or says it accepts no email. Only the domain names (the part after the @) are sent, to Cloudflare’s public DNS service; the addresses never leave your browser. Big providers like Gmail and Outlook are skipped.
The clean list keeps your original order, one address per line in lower case (or comma or semicolon separated, for pasting into an email’s To: field). Lines can hold more than an address: from Amy Smith <amy@acme.com> or a spreadsheet row, the address is kept and the rest is dropped.
How to clean an email list
- Copy the email column from your spreadsheet, email service or CRM export and paste it into the box, or open a .txt or .csv file with File.
- Choose what to remove. The defaults suit most mailing lists; tick Check online to also validate each domain.
- Press Clean list, look over what was fixed and removed, then press Copy or File → Download as .txt and import the clean list.
Why clean an email list?
Every address that bounces tells mail providers that a sender’s list is out of date. With too many bounces, messages start landing in spam folders, and email marketing services may pause the account. Typos, abandoned and throwaway sign-ups also make a list look bigger than it is, and many services charge by the number of subscribers.
Regular email list cleaning (often called email list hygiene) keeps those numbers down. Cleaning before a big send, or before importing a list into a new service, removes the problems that are certain to bounce, for free.
Email list cleaning vs. bulk email verification
This email list validation catches every address that can’t work. What it can’t check is whether a particular mailbox exists. The only way to find out is to start delivering a message to the receiving mail server and see whether it refuses, which a web page can’t do. A paid bulk email verifier (an email verification service) does it from its own servers, and even they can’t always tell: some servers accept every address and bounce the message later. So amy@acme.com passes here if acme.com takes email, even if Amy left last year.
Related clean-ups
- Addresses buried in text, email threads or a web page? Pull them out first with the email extractor.
- Taking out people who unsubscribed or bounced last time: remove one list from another, matching the email address in each line.
- Near-duplicates that aren’t typos of a big provider, like
jon.smith@acme.comandjon.smyth@acme.com: find near matches. - Grouping the clean list by company: sort by email domain.
Please only email people who have agreed to hear from you. Sending bulk mail to bought or scraped lists breaks anti-spam laws in most countries.
A messy sign-up list
Amy.Smith@Gmial.com bob@acme.con carla@mailinator.com amy.smith@gmail.com dan@@example.org info@acme.com eve.jones+news@gmail.com evejones@gmail.com noreply@shop.example.com Frank Lee <frank@acme.com>
amy.smith@gmail.com bob@acme.com info@acme.com eve.jones+news@gmail.com frank@acme.com
Addresses copied from an email’s To: line
Amy Smith <amy@acme.com>; bob@acme.com; "Smith, Amy" <AMY@ACME.COM>; carl@acme
amy@acme.com bob@acme.com
Questions
Is my list uploaded anywhere?
No. Cleaning happens inside your web browser. Only if you tick Check online are the domain names, the part after the @, sent to Cloudflare’s public DNS service to look up their mail servers, the same lookup any computer makes before sending an email. The addresses themselves never leave your computer.
Can I check if one email address is valid?
Yes. Paste a single address and press Clean list: it works as an email validator for one address too. It checks that the address is written correctly, that its ending exists and that it isn’t a throwaway address, and with Check online ticked, that the domain accepts email.
Does it tell me whether a mailbox exists?
No. To verify an email address that far needs a conversation with the receiving mail server, which only a paid verification service can have. This tool removes everything that is sure to fail, and with Check online ticked, addresses at domains that can’t receive email.
Why was an address I know is real removed?
Every removal is listed with its reason, and Undo brings your original list back. Throwaway domains come from a public list that is occasionally wrong; untick Remove throwaway addresses and clean again to keep them.
How many addresses can it clean?
Tens of thousands at once. The online check looks up each different domain once, so it takes longer for lists with thousands of different domains.
Does it change my addresses?
Only to fix a typo it is sure about (every fix is listed) and to put addresses in lower case, which makes no difference to delivery in practice.