Free email domain API

// Express signup middleware
app.post('/signup', async (req, res, next) => {
  const domain = String(req.body.email).split('@').pop().toLowerCase();
  const v = await fetch('https://emaildomaincheck.com/api/email-domain/' + domain).then(r => r.json());
  if (v.disposable === 'confirmed') {
    return res.status(422).json({ error: 'Please use a permanent email address.' });
  }
  req.requireEmailConfirmation = v.disposable === 'reported';
  next();
});

// Laravel custom validation rule
Validator::extend('not_disposable', function ($attr, $value) {
    $domain = strtolower(substr(strrchr($value, '@'), 1));
    $v = Http::get('https://emaildomaincheck.com/api/email-domain/' . $domain)->json();
    return ($v['disposable'] ?? 'no') !== 'confirmed';
}, 'Please use a permanent email address.');

# Django form validator
import requests
from django.core.exceptions import ValidationError

def validate_not_disposable(email):
    domain = email.rsplit('@', 1)[-1].lower()
    v = requests.get('https://emaildomaincheck.com/api/email-domain/' + domain, timeout=5).json()
    if v.get('disposable') == 'confirmed':
        raise ValidationError('Please use a permanent email address.')

# Rails model validation
validate :email_not_disposable, on: :create

def email_not_disposable
  domain = email.to_s.split('@').last&.downcase
  v = JSON.parse(Net::HTTP.get(URI("https://emaildomaincheck.com/api/email-domain/#{domain}")))
  errors.add(:email, 'temporary addresses are not accepted') if v['disposable'] == 'confirmed'
end

// WordPress: block disposable signups (functions.php)
add_filter('registration_errors', function ($errors, $login, $email) {
    $domain = strtolower(substr(strrchr($email, '@'), 1));
    $v = json_decode(wp_remote_retrieve_body(wp_remote_get(
        'https://emaildomaincheck.com/api/email-domain/' . $domain)), true);
    if (($v['disposable'] ?? 'no') === 'confirmed') {
        $errors->add('disposable_email', 'Please use a permanent email address.');
    }
    return $errors;
}, 10, 3);