Anti-Spam Measures

Anti-Spam Measures for Contact Forms on International Websites

Introduction

When running a WordPress website for an international audience, it’s common to face an overwhelming number of spam messages through your contact forms. Especially for English-language or multilingual sites, spam bots often flood forms with unwanted content. Ignoring this problem increases management workload and risks missing important customer inquiries. This article, written in a diary-style narrative, shares practical ways to implement anti-spam measures for contact forms on international WordPress sites.

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Step-by-Step Guide

There are several approaches to blocking spam. Combining them yields the best results.

1. Implement Google reCAPTCHA
   Adding Google reCAPTCHA helps block automated submissions. Using reCAPTCHA v3 provides invisible protection without requiring user interaction.
   Google reCAPTCHA
2. Use the Akismet Anti-Spam Plugin
   Akismet automatically analyzes form submissions and filters out spam messages. It’s one of the most reliable WordPress solutions.
3. Leverage Contact Form 7’s Built-in Features
   Contact Form 7 allows adding simple spam-prevention fields, such as a math quiz or challenge question. This blocks many bots.
4. Block Specific IPs or Email Domains
   By adding custom code in functions.php, you can reject submissions from suspicious sources.

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Code Example: Blocking Spam Emails by Domain

This PHP code blocks form submissions from certain email domains in Contact Form 7.

Here is the code:

// Block specific email domains
add_filter('wpcf7_validate_email*', 'block_spam_domain', 20, 2);
function block_spam_domain($result, $tag) {
    $type = $tag['type'];
    $name = $tag['name'];

    if ('email' == $type || 'email*' == $type) {
        $email = isset($_POST[$name]) ? trim($_POST[$name]) : '';
        if (strpos($email, '@example.com') !== false) {
            $result->invalidate($tag, 'This domain is not allowed.');
        }
    }
    return $result;
}

Key Points

• Replace @example.com with the spam domain you want to block.
• You can add multiple rules to cover different domains or patterns.

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Testing & Practical Use

1. After adding the code, test by submitting a form with the blocked domain to ensure the restriction works.
2. Combine this with reCAPTCHA and Akismet for maximum protection.
3. While it’s impossible to eliminate spam entirely, you can reduce it by over 90%.

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Conclusion

Spam protection is essential for international WordPress sites. By combining reCAPTCHA, Akismet, Contact Form 7 features, and custom code, you can drastically reduce spam while keeping your site user-friendly. The goal is to balance security with usability so real customer inquiries are never lost.