How to Validate Email Addresses in PHP (2026 Guide)

1. Format check with filter_var

$email = trim($_POST['email'] ?? '');

if (filter_var($email, FILTER_VALIDATE_EMAIL) === false) {
    exit('Please enter a valid email address.');
}

2. Does the domain accept email?

$domain = substr(strrchr($email, '@'), 1);
if (!checkdnsrr($domain, 'MX') && !checkdnsrr($domain, 'A')) {
    exit('This email domain does not exist.');
}

3. Check the mailbox with the API

function validate_email_api(string $email): array {
    $ch = curl_init('https://api.emailvalidation.io/v1/info?email=' . urlencode($email));
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT => 30,
        CURLOPT_HTTPHEADER => ['apikey: ' . getenv('EMAILVALIDATION_API_KEY')],
    ]);
    $body = curl_exec($ch);
    curl_close($ch);
    return json_decode($body, true) ?? [];
}

$result = validate_email_api($email);
if (($result['state'] ?? '') === 'undeliverable' || !empty($result['disposable'])) {
    exit('Please use a valid, permanent email address.');
}

Laravel

$request->validate([
    'email' => ['required', 'email:rfc,dns', function ($attribute, $value, $fail) {
        $r = Http::withHeaders(['apikey' => config('services.emailvalidation.key')])
            ->timeout(10)
            ->get('https://api.emailvalidation.io/v1/info', ['email' => $value])
            ->json();
        if (($r['state'] ?? null) === 'undeliverable' || ($r['disposable'] ?? false)) {
            $fail('Please use a valid, permanent email address.');
        }
    }],
]);

If the API call times out, let the address through rather than blocking the sign-up.

Frequently asked questions

Is filter_var FILTER_VALIDATE_EMAIL enough?

It is a solid format check, but it accepts addresses on domains that do not exist and mailboxes that were never created. Combine it with an MX check and, for sign-ups and imports, an API check.

How do I validate email DNS in Laravel?

Use the rule 'email:rfc,dns'. It checks the format and that the domain has DNS records, but not whether the mailbox exists.

{ "email": "support@emailvalidation.io", "domain": "emailvalidation.io", "format_valid": true, "mx_found": true, "smtp_check": true, "disposable": false, "role": true, "free": false, "score": 0.64, "state": "deliverable", "reason": "valid_mailbox" }

Validate email addresses in PHP