@lacspace/email-validate

Email validation that goes beyond a regex — disposable detection, typo suggestions, normalization.

A regex tells you an address is shaped right. This tells you it's a mailinator throwaway, that gmial.com should be gmail.com, that info@ is a role mailbox, and gives you a normalized canonical form for de-duping users.

• ✅ Robust syntax + length checks (RFC-5321-ish)
• 🗑️ Disposable / temp-mail detection
• 💡 "Did you mean?" typo suggestions (gmial.com → gmail.com)
• 👥 Role-address (info@, admin@) & free-provider flags
• 🔤 normalizeEmail — Gmail dots/+tags stripped, lowercased (great for de-dupe)
• ⚡ Zero dependencies · 🌍 isomorphic · 📦 ESM + CJS · fully typed

New in 1.1.0 — a stronger, superset RFC-5322 syntax check (isValidEmailRFC5322) that accepts quoted local parts and IP-literal domains; whole-address isDisposableEmail() / isRoleAccount() wrappers; and normalizeEmail(email, opts?) with per-rule toggles. All additive — every existing export is unchanged.

What's new in 1.2.0

• Control characters are rejected. isValidEmail("[email protected]\n") used to return true because the input was trimmed first. A CR, LF, tab or NUL is never part of an address, and a trailing one carried into a mail header is how header injection starts. Surrounding spaces are still trimmed.
• Unicode domains are valid. user@bücher.example and user@例え.テスト pass, checked in their ASCII (punycode) form. normalizeEmail maps both spellings to the same key. New export: toAsciiDomain(domain).
• Internationalised local parts are opt-in. isValidEmail("mü[email protected]", { allowUnicodeLocal: true }) accepts RFC 6531 addresses. It is off by default, because the whole mail path must support SMTPUTF8. The 64 limit counts octets.
• isFreeProvider knows the world's big providers: QQ, 163, 126, Naver, Daum, GMX, web.de, T-Online, Orange, Libero, Seznam, WP, Yahoo Japan, UOL, and more.

Install

npm install @lacspace/email-validate      # or pnpm add / yarn add / bun add

One call, everything you need

import { validateEmail } from "@lacspace/email-validate";

validateEmail("[email protected]");
// {
//   valid: true,
//   normalized: "[email protected]",
//   local: "john.doe+news",
//   domain: "gmial.com",
//   disposable: false,
//   role: false,
//   free: false,
//   suggestion: "[email protected]"   // ← typo caught
// }

validateEmail("[email protected]").disposable; // true
validateEmail("[email protected]").role;          // true
validateEmail("nope@@bad").valid;                 // false

Individual helpers

import {
  isValidEmail, normalizeEmail, isDisposable, isRoleAddress, isFreeProvider, suggestEmail,
} from "@lacspace/email-validate";

isValidEmail("[email protected]");                       // true
normalizeEmail("[email protected]");   // "[email protected]"
isDisposable("guerrillamail.com");            // true
isRoleAddress("support");                      // true
isFreeProvider("yahoo.com");                   // true
suggestEmail("[email protected]");                  // "[email protected]"

Real-world: clean a signup form

const r = validateEmail(input);
if (!r.valid) return fail("Please enter a valid email.");
if (r.suggestion) return confirm(`Did you mean ${r.suggestion}?`);
if (r.disposable) return fail("Please use a permanent email address.");
await createUser({ email: r.normalized }); // store the canonical form

Customize

validateEmail(input, {
  extraDisposable: ["mycompany-temp.com"], // add your own throwaway domains
  suggestions: false,                       // turn off typo suggestions
});

You can also read/extend the exported sets: DISPOSABLE_DOMAINS, FREE_PROVIDERS, ROLE_LOCALS.

Advanced syntax & helpers (v1.1.0)

import {
  isValidEmailRFC5322, isDisposableEmail, isRoleAccount, normalizeEmail,
} from "@lacspace/email-validate";

// Stronger RFC-5322 syntax — a SUPERSET of isValidEmail:
isValidEmailRFC5322('"john doe"@example.com');   // true  (quoted local part)
isValidEmailRFC5322("user@[192.168.0.1]");        // true  (IPv4 literal)
isValidEmailRFC5322("user@[IPv6:2001:db8::1]");   // true  (IPv6 literal)
isValidEmailRFC5322("[email protected]");          // false (consecutive dots)
isValidEmailRFC5322("a".repeat(65) + "@x.com");   // false (local > 64)

// Whole-address convenience wrappers:
isDisposableEmail("[email protected]");            // true
isRoleAccount("[email protected]");         // true  (ignores +tag)

// normalizeEmail now takes optional per-rule toggles (defaults = v1.0 behaviour):
normalizeEmail("[email protected]", { gmailRemoveDots: false });  // "[email protected]"
normalizeEmail("[email protected]",   { removeSubaddress: false });  // "[email protected]"

API

| Export | Signature | What it does | | --- | --- | --- | | isValidEmailRFC5322 | (email, opts?: { allowQuoted?; allowIpLiteral? }) → boolean | Stronger, superset syntax check: quoted local parts + IP-literal (IPv4/IPv6) domains, RFC length limits (local ≤64, domain ≤255, total ≤254), consecutive/edge-dot rejection. No network. | | isDisposableEmail | (email, extra?: string[]) → boolean | Disposable check taking the whole address (companion to isDisposable(domain)). | | isRoleAccount | (email) → boolean | Role-mailbox check taking the whole address, +tag-aware (companion to isRoleAddress(local)). | | normalizeEmail | (email, opts?: NormalizeOptions) → string | Canonical form. New optional opts: gmailRemoveDots, gmailRemoveSubaddress, removeSubaddress, lowercaseLocal (all default true — v1.0 behaviour unchanged). |

The Lacspace MailKit

| Package | For | | --- | --- | | @lacspace/mailer | Send email over SMTP | | @lacspace/email-templates | Build responsive HTML emails | | @lacspace/email-validate | Validate & normalize addresses (this package) | | @lacspace/email-verify | MX + SMTP deliverability checks |

Licensing

This package is free under the Lacspace Free Licence — permissive freedoms. Use it in personal and commercial projects at no cost; just keep the notice.

Not every Lacspace package is free. We also offer Commercial (paid), Client-specific, and Private (proprietary) packages under separate terms. See the full Lacspace Licence Centre.

The Lacspace Developer Platform

@lacspace/email-validate is part of 80+ zero-dependency, isomorphic TypeScript packages — one standard library for the modern web. Explore the ecosystem:

• 📦 This package, documented — https://developer.lacspace.com/packages/email-validate
• 🗂️ All 80+ packages — https://developer.lacspace.com/packages
• 🧭 Developer handbook — guides & runnable recipes — https://developer.lacspace.com/handbook
• 🧪 Live playground — run any package in your browser — https://developer.lacspace.com/playground
• 🖥️ Finished app templates — https://templates.lacspace.com
• 🚀 Scaffold a full app — npm create lacspace-app@latest

Free under the Lacspace Free Licence — a permissive, free-to-use licence.