Initial commit

contact-form-7-email-validator.php

+/*
+Plugin Name: Contact Form 7 Email Validator
+Plugin URI: https://wordpress.org/plugins/contact-form-7-email-validator
+Description: Validate email addresses in Contact Form 7 submissions.
+Version: 0.1
+Author: Anton Sarukhanov
+Author URI: https://ant.sr
+License: MIT
+*/
+
+add_filter('wpcf7_validate_email*', 'wpcf7ev_validate_email', 20, 2);
+
+function wpcf7ev_validate_email($result, $tag) {
+    $tag = new WPCF7_FormTag($tag);
+    $email = isset($_POST[$tag->name]) ? trim($_POST[$tag->name]) : '';
+
+    $mailboxlayer_access_key = 'YOUR_ACCESS_KEY';
+
+    $ch = curl_init('http://apilayer.net/api/check?access_key='.$mailboxlayer_access_key.'&email='.$email.'');
+    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+    $json = curl_exec($ch);
+    curl_close($ch);
+    $validationResult = json_decode($json, true);
+
+    if (!$validationResult['smtp_check']) {
+        $result->invalidate($tag, "This email address could not be verified!");
+    }
+
+    return $result;
+}