Code & files / Email
Email Address Validator: Check Format, Typos, and Duplicates
Check email addresses in bulk without sending anything: each address is tested against the rules mail servers follow, common typos such as gmial.com are spotted with a suggested fix, role addresses like info@ are flagged, and duplicates are removed, ready to copy back.
Email Address Validator: Check Format, Typos, and Duplicates: An address needs one @, at most 64 characters before it and 254 in all, no leading, trailing, or doubled dots before the @, and a domain made of letters, digits, and hyphens with a valid ending; quoted local parts, international domains, and IP literals are accepted. A domain one letter swap away from a big provider, such as gmial.com, gets a suggestion. Runs 100% locally in your browser with zero server file uploads.
- Category
- Developer tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
5 addresses: 3 valid, 2 invalid, 0 duplicates.
| Address | Result | Notes |
|---|---|---|
| sam@example.com | Valid format | |
| ana.silva@gmial.com | Valid format | Did you mean ana.silva@gmail.com? |
| info@shop.co.uk | Valid format | Role address, often not read by one person |
| wrong@@example.com | Characters not allowed before @ | |
| bob@example | The domain has no ending such as .com |
This checks the format against the rules mail servers follow, spots common typos in big providers' domains, and flags role addresses and duplicates. It does not contact any server, so it cannot tell whether a mailbox exists; the only sure test is a confirmation email. Nothing you paste is uploaded.
Rules
The checks follow RFC 5321 and RFC 5322 as mail servers apply them in practice; rare legal forms such as comments in addresses are rejected because almost no service accepts them.
Cleaning lists
To remove duplicate rows from a whole spreadsheet, use the data deduplicator.
How to use it
- Paste addresses, one per line or separated by commas.
- Read the result and notes for each address.
- Copy the valid addresses without duplicates.
Privacy & limitations
Nothing you paste leaves your browser.
Related tools
Frequently asked questions
Does a valid result mean the mailbox exists?
No: this checks the format only and never contacts a mail server; send a confirmation email to be sure.
Why flag info@ or support@?
Role addresses are often shared or filtered, so they suit business contact but not personal sign-ups.
Are addresses case-sensitive?
Domains are not, and in practice almost no mail server treats the part before @ as case-sensitive, so duplicates are compared without case.
Free tool · runs in your browser · no account required