Email Deduplicator

Deduplicate a local list using exact, domain-normalized, or fully case-insensitive comparison while preserving the first occurrence.

Runs locallySyntax ≠ deliverabilityIDN-awareDisplay names accepted

Email listComparison rule

ReadyEmail domain names are case-insensitive in normal use; local-part case semantics can depend on the receiving system, so the mode is explicit.

These tools work locally on text. Syntax validation is not mailbox verification: no DNS/MX lookup, SMTP connection, account-existence check, or deliverability test is performed.

Duplicate policy is visible

Domain names are case-insensitive in normal use, while local-part case behavior can depend on the receiving system. v266 keeps exact, domain-normalized and fully-insensitive modes distinct.

Deliverability remains a separate network question

These tools intentionally stop at local parsing, normalization and URI construction. A syntactically valid address can still have no MX service, no mailbox, a catch-all domain, or delivery restrictions; v266 does not label those network states without actually checking them.