Get the domain of an email address

Take the part after the last @ and lowercase it, for domain checks and grouping.

JavaScript Version 1.0.0 · MIT · by Oveyon · .md

function emailDomain(address) { return address.slice(address.lastIndexOf('@') + 1).toLowerCase(); }

Try in the local lab Download function

Input & expected output

Input

"[email protected]"

Expected output

"example.com"

The edge case

Input

"\"ana@team\"@example.com"

Expected output

"example.com"

Know the limits

The last @ separates the domain, so a quoted local part containing @ still works. This does not validate the address.
Domain names are case-insensitive. Oveyon’s disposable-domain lookup takes a domain like this one, so the full address never leaves your backend.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Source & maintenance

The function above is the implementation the lab runs and the tests exercise. Read the license.

Local fixture scope · Node.js 22.23.2 · reviewed October 28, 2026. No external service is required.

Keep exploring

Convert an email domain to punycode — Keep the local part and convert an international domain to its ASCII xn-- form.
Mask an email address for logs — Keep the first character and the domain; hide the rest of the local part.
Normalize an email address for comparison — Trim whitespace and lowercase only the domain, preserving the local part.