Email normalizer

Normalize email addresses by lowercasing them, stripping plus tags and Gmail dots, and removing duplicates.

Lowercase the local part

Apply provider rules

Gmail dots and tags, Outlook, Yahoo, iCloud, Proton, Fastmail.

Strip +tags for all domains

Remove duplicates

Email addresses

Try:

Normalized addresses

These rules are heuristics. Providers decide how their addresses work and can change it, and two addresses that normalize the same are not proven to reach the same inbox. Use the result to spot likely duplicates, not to rewrite the addresses people gave you. Validation is pragmatic, not a full RFC 5322 check.