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Paste your email list
Drop in emails one per line or paste a CSV cell - the parser handles commas, semicolons, tabs, and newlines.
Email List Hygiene
Free Email List Deduplicator
An email list deduplicator is a tool that removes duplicate email addresses from a list. This free deduplicator runs entirely in your browser - paste your list, and duplicates are stripped instantly.
Built for marketers and developers cleaning CSV exports before an ESP upload. Normalize casing, whitespace, Gmail plus-addresses, and Gmail dots - or flip on strict mode to keep only byte-for-byte duplicates. Nothing leaves your browser.
Paste your email list
One per line, or paste CSV/TSV - separators are auto-detected.
Cleaned list
Deduplicated emails, ready to copy or export.
How to deduplicate an email list
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Adjust normalization options
Toggle lowercase, whitespace trimming, and Gmail plus or dot normalization, or flip on strict mode to keep only byte-for-byte duplicates.
3
Copy or download the cleaned list
Use the copy button to drop the deduped list into your ESP, or download deduplicated-emails.txt for upload.
Frequently asked questions
What does an email list deduplicator do?
An email list deduplicator scans a list of email addresses and removes duplicates so each subscriber appears only once. This tool also normalizes common variations like casing, surrounding whitespace, and Gmail-specific aliases so addresses that route to the same inbox are collapsed together.
How are Gmail plus-addresses (user+tag@gmail.com) handled?
When the Gmail plus-addressing option is on, anything after the plus sign in the local part is stripped for gmail.com and googlemail.com addresses, so user+promo@gmail.com and user+news@gmail.com are treated as the same address. Other domains are left alone because plus-addressing is not universally aliased.
Are my emails uploaded to a server?
No. The deduplicator runs entirely in your browser using JavaScript. Nothing is sent to MailParse, no data is logged, and your list is never written to disk on our side - close the tab and the list is gone.
What's the difference between strict mode and normalized mode?
Normalized mode (the default) collapses casing, whitespace, Gmail dots, and Gmail plus-addressing so logically identical addresses are merged. Strict mode disables every normalization and only removes byte-for-byte exact duplicates - useful when you want to keep mixed-case or aliased addresses as separate rows.
Can I deduplicate a CSV email list with this tool?
Yes. Paste a CSV column or row and the parser splits on commas, semicolons, tabs, newlines, and spaces, so any common export format works. If your CSV has a header row like 'email' or 'Email Address', the validator will flag it as invalid so it does not pollute the cleaned output.
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