Prevent Duplicate Gmail Accounts Securely

Important Warning Before We Start 🛑
This topic is for awareness and security purposes only.
It’s not about breaking websites or abusing signup systems 👌
The goal is to help you, as a developer, understand the problem and fix it the right way 🔐

The Problem: Multiple Accounts Using the Same Email ❌​

One of the most common issues in user registration systems is allowing users to create multiple accounts with the same email 😤
The main reason behind this issue is how Gmail handles email addresses.
Google ignores dots (.) in Gmail usernames.
For example, if your email is: example@gmail.com
You can also use:

• e.xample@gmail.com
• ex.ample@gmail.com
• exam.ple@gmail.com
• e.x.a.m.p.l.e@gmail.com

📩 All of them go to the same inbox 💡
However, most databases treat these as different emails, so validation passes without any problem.

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Why This Is a Serious Security Risk 🧠​

Allowing duplicate email registrations can lead to:

• 🚫 Fake and spam accounts
• 💾 Unnecessary server resource usage
• 🎁 Abuse of free trials and bonuses
• 🔗 Broken referral or reward systems

That’s why this issue must be handled properly 🔒

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The Correct Way to Prevent Duplicate Accounts 🛡️​

Let’s solve this problem step by step as developers 👨‍💻

Block Temporary (Disposable) Email Addresses​

🔵 Temporary email services are a huge risk if left unchecked 😑

The Solution​

Use a ready-made package with a large and updated database of disposable email domains 👇
🔗 https://github.com/Propaganistas/Laravel-Disposable-Email

Why This Works​

• ✅ Over 135,000 disposable email domains
• 🔄 Regularly updated

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Automatically Update the Disposable Email List​

🧩 To keep the list always up to date, schedule a weekly update using Cron:

$schedule->command('disposable:update')->weekly();

🚫 This ensures fake and temporary emails are blocked automatically.

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Normalize Gmail Emails by Removing Dots​

🔵 This is the most important step 👌
Before validation or saving the email to the database, you must clean Gmail addresses.

The Idea ✨​

For any Gmail address:

• Remove all dots (.)
• Store the normalized email in the database

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PHP Example: Gmail Email Normalization 💻​

$email = strtolower($request->email);

if (str_contains($email, '@gmail.com')) {
    [$name, $domain] = explode('@', $email);
    $name = str_replace('.', '', $name);
    $email = $name . '@' . $domain;
}

📌 Result:

• example@gmail.com
• e.xa.mple@gmail.com

➡️ Both are treated as one email in the database ✅

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Protect Your Signup System from Bots 🤖​

Even after fixing email issues, bots are still a threat.
The simplest and most effective solutions include:

• Google reCAPTCHA
• Cloudflare Turnstile
• Any reliable bot detection system

This helps prevent:

• 🚫 Automated registrations
• 🚫 Spam accounts
• 🚫 Brute-force attacks

And honestly… it saves a lot of headaches 😎

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Final Summary ✅​

If you run a user registration system, make sure to:

• ✔️ Block disposable email addresses
• ✔️ Normalize Gmail emails (remove dots)
• ✔️ Enable bot protection

This guarantees a clean, secure, and abuse-free signup system 👏
And that’s a core foundation for any successful website 🔐