is-this-mail-fake 🚫

Detect fake, disposable, and temporary email addresses instantly. 670+ domains built-in. Zero dependencies. Works in Node + Browser.

Install

npm install is-this-mail-fake

Quick Start

import { isFake, isReal } from 'is-this-mail-fake';

isFake('[email protected]')    // true
isFake('[email protected]')       // true
isFake('[email protected]')     // true
isFake('[email protected]')        // false
isFake('[email protected]')       // false

API

isFake(email) → boolean

Returns true if the email uses a disposable/fake provider.

import { isFake } from 'is-this-mail-fake';

isFake('[email protected]')   // true
isFake('[email protected]')// true
isFake('[email protected]')       // false
isFake('invalid-email')         // false  (invalid = not fake)
isFake(null)                    // false  (safe — no crash)

isReal(email) → boolean

Opposite of isFake. Returns true if email looks legitimate.

import { isReal } from 'is-this-mail-fake';

isReal('[email protected]')         // true
isReal('[email protected]')    // false

check(email) → object

Full result with domain and reason.

import { check } from 'is-this-mail-fake';

check('[email protected]')
// {
//   email:  '[email protected]',
//   domain: 'mailinator.com',
//   fake:   true,
//   reason: 'disposable'
// }

check('[email protected]')
// { email: '[email protected]', domain: 'gmail.com', fake: false, reason: 'clean' }

check('not-an-email')
// { email: 'not-an-email', domain: null, fake: false, reason: 'invalid_email' }

Reasons:

| Reason | Meaning | |---|---| | disposable | Domain is in the built-in blocklist | | disposable_subdomain | Subdomain of a known disposable provider | | blacklisted | In your custom blacklist | | whitelisted | In your custom whitelist — trusted | | clean | Not found in any list | | invalid_email | Not a valid email format |

checkMany(emails[]) → object[]

Check multiple emails at once.

import { checkMany } from 'is-this-mail-fake';

checkMany(['[email protected]', '[email protected]', '[email protected]'])
// [
//   { email: '[email protected]',       fake: false, reason: 'clean' },
//   { email: '[email protected]',  fake: true,  reason: 'disposable' },
//   { email: '[email protected]',     fake: true,  reason: 'disposable' },
// ]

filterReal(emails[]) → string[]

Keep only real emails from a list.

import { filterReal } from 'is-this-mail-fake';

filterReal(['[email protected]', '[email protected]', '[email protected]'])
// ['[email protected]', '[email protected]']

filterFake(emails[]) → string[]

Keep only fake emails from a list.

import { filterFake } from 'is-this-mail-fake';

filterFake(['[email protected]', '[email protected]', '[email protected]'])
// ['[email protected]', '[email protected]']

isFakeDomain(domain) → boolean

Check a domain directly without a full email.

import { isFakeDomain } from 'is-this-mail-fake';

isFakeDomain('mailinator.com')   // true
isFakeDomain('gmail.com')        // false

blacklist(domain | domain[]) — Custom blocklist

Add your own domains to always treat as fake.

import { blacklist, isFake } from 'is-this-mail-fake';

blacklist('internal-test.xyz');
blacklist(['disposable.io', 'temp-users.co']);

isFake('[email protected]')   // true

whitelist(domain | domain[]) — Custom allowlist

Trust specific domains — always bypass all checks.

import { whitelist, isReal } from 'is-this-mail-fake';

// Your own org domains
whitelist('enrole.ai');
whitelist(['growbharatbiz.com', 'logixbuilt.com']);

isReal('[email protected]')   // true  (even if it ever appeared in a list)

Unknown domains are always treated as real. Only domains explicitly in the built-in blocklist are flagged. Use whitelist() to guarantee your org domains are never blocked.

getLists() — See custom lists

import { getLists } from 'is-this-mail-fake';

getLists()
// { blacklist: ['internal-test.xyz'], whitelist: ['enrole.ai'] }

domainCount() → number

Total domains in built-in blocklist.

import { domainCount } from 'is-this-mail-fake';

domainCount()   // 670

CLI

# Single email
npx is-this-mail-fake [email protected]

# Multiple emails at once
npx is-this-mail-fake [email protected] [email protected] [email protected]

# JSON output
npx is-this-mail-fake [email protected] --json

Output:

  ✗  FAKE   [email protected]          (disposable)
  ✓  REAL   [email protected]
  ✗  FAKE   [email protected]             (disposable)

Exit code 1 if any email is fake — useful for CI/scripts.

Common Use Cases

Signup form validation (Node.js)

import { isFake } from 'is-this-mail-fake';

app.post('/register', (req, res) => {
  const { email } = req.body;

  if (isFake(email)) {
    return res.status(400).json({
      error: 'Disposable email addresses are not allowed. Please use a real email.'
    });
  }

  // proceed with registration...
});

NestJS / class-validator pipe

import { isFake } from 'is-this-mail-fake';
import { registerDecorator } from 'class-validator';

export function IsNotFakeEmail() {
  return registerDecorator({
    name: 'isNotFakeEmail',
    validator: {
      validate: (email: string) => !isFake(email),
      defaultMessage: () => 'Disposable email addresses are not allowed',
    },
  });
}

// Usage in DTO:
class RegisterDto {
  @IsEmail()
  @IsNotFakeEmail()
  email: string;
}

React form validation

import { isFake } from 'is-this-mail-fake';

function EmailInput({ value, onChange }) {
  const fake = value && isFake(value);

  return (
    <div>
      <input value={value} onChange={e => onChange(e.target.value)} />
      {fake && <p style={{ color: 'red' }}>Disposable emails are not allowed</p>}
    </div>
  );
}

Clean a mailing list

import { filterReal, checkMany } from 'is-this-mail-fake';

const emailList = ['[email protected]', '[email protected]', '[email protected]', '[email protected]'];

// Keep only real
const clean = filterReal(emailList);
// ['[email protected]', '[email protected]']

// Get details on all
const report = checkMany(emailList);
const fakeCount = report.filter(r => r.fake).length;
console.log(`Removed ${fakeCount} disposable emails`);

CI — block fake emails in tests

# In your CI pipeline
npx is-this-mail-fake $TEST_EMAIL
# exits 1 if fake — fails the pipeline

How It Works

1. Extracts the domain from the email ([email protected] → mailinator.com)
2. Custom whitelist check — whitelisted domains always pass (your org domains)
3. Custom blacklist check — your own blocked domains
4. Built-in list lookup — O(1) Set lookup against 670+ known disposable domains
5. Wildcard match — catches subdomains like bob.mailinator.com

All lookups are in-memory and synchronous — no network calls, no async, no latency.

License

MIT © Adarsh

Contributing

PRs welcome! To add more domains, edit src/domains.js.