Email Validator — bulk syntax check & cleanup

Paste up to thousands of email addresses, get a per-line valid/invalid/typo breakdown, and copy back a clean deduplicated list. Common typos like gmial.com are flagged with the right fix.

What this validator checks

Three things, in order: syntax (does the address match a permissive RFC 5322-style pattern), domain typos (is the domain a near-miss for a popular provider — gmial.com, hotnail.com, outlook.con), and duplicates (case-insensitive, after typo fix). Nothing is sent to a server, so the tool is safe with your CRM export, mailing list or unsubscribed user list.

What it deliberately doesn't do: connect to mail servers (SMTP probing) to confirm the inbox actually exists. SMTP probing requires server-side code and triggers spam-detection on the receiving end. For deliverability checks, use a paid validation service (ZeroBounce, NeverBounce). For syntax + obvious-typo cleanup before that, this tool is plenty.

How to use this tool

Paste your email addresses, one per line. Whitespace and empty lines are ignored.
Read the per-line results: green ✓ for valid, amber ⚠ for syntactically valid but with a likely-typo domain (with the suggested fix), red ✗ for syntax errors. Duplicates are flagged with (duplicate).
Click Copy valid to put a cleaned, deduplicated list (with typo fixes applied) on your clipboard. Paste into your CRM, mailing list import, or wherever you need clean addresses.

Frequently asked questions

Does this verify the email actually exists?

No. Verifying inbox existence requires SMTP probing the receiving server, which is server-side, slow, and may flag your IP as spammy. This tool only verifies syntax and flags likely typos. For real deliverability checks, use a paid service.

What syntax does it accept?

A practical RFC 5322-style pattern that covers the addresses you actually see in the wild: alphanumerics, dots, plus signs and most special characters in the local part; standard domain syntax with at least one dot. It deliberately rejects '..', leading dots, and addresses without a TLD.

Why does it flag gmial.com but not gmail.fr?

Because gmial is a known typo of gmail, while gmail.fr is a perfectly valid Google Workspace domain on the .fr TLD. The typo list is curated to common misspellings of major providers; rare-domain typos slip through.

How does dedupe work?

Case-insensitive on both local part and domain (alice@example.com and Alice@Example.com are the same person). When a typo is suggested, dedupe uses the corrected form so 'alice@gmial.com' and 'alice@gmail.com' don't both appear in the output.

Is this safe for my customer list?

Yes. Everything runs in your browser. The email addresses you paste never leave your machine — no upload, no server roundtrip. Safe for CRM exports, GDPR-sensitive lists, and so on.

Common use cases

Where validating before sending saves real money.

Cleaning a mailing list before import

Mailchimp, Brevo, ActiveCampaign and others charge per contact. Spending two minutes pruning invalid and duplicate entries directly saves money on the next billing tier.

Auditing a CRM export

When migrating from one CRM to another, run the export through this tool first. Typo fixes alone often recover 1-2% of contacts that would otherwise bounce on the next campaign.

Cleaning leads from a CSV

Sales lists from third-party providers often contain typos and duplicates. Run them through here before importing — your sales team will thank you for not sending them dead emails to chase.

Pre-flight check for a transactional send

About to send a one-off invoice batch to 200 customers? Quick paste-and-validate before hitting send catches the inevitable 2-3 typo'd entries before they hard-bounce.

Tips and shortcuts

Habits that keep your sender reputation clean.

Validate at signup

Adding the same regex to your signup form prevents most typos from ever reaching your list. Combine with a 'did you mean gmail.com?' nudge for the typo'd domains; users typically self-correct.

Don't accept role addresses for marketing

info@, contact@, support@ tend to be shared inboxes that mark all marketing as spam. Either skip them or send only transactional content; never include in a marketing send.

Confirm via double opt-in

Even after passing syntax checks, the address might still belong to someone who didn't sign up. Double opt-in (send a confirmation link, only add after click) keeps your bounce rate low and protects your sender reputation.

Validate periodically

An address that was valid 18 months ago may now be a hard bounce (employee changed jobs, domain was decommissioned). Re-validate with a paid service every 6-12 months to keep your list healthy.