Laravel 12 Validation Form Rules Explained: A Complete Guide with Examples

Validations are crucial in web applications to ensure that user-submitted data is correct, secure, and follows business rules. Laravel provides a simple yet powerful way to validate incoming data.

In this guide, we’ll cover:
✅ Basic Form Request Validation
✅ Custom Validation Rules
✅ Real-Time Validation with Livewire (Optional)
✅ Error Handling & Displaying Messages

Let’s dive in!

1. Why Validations Are Important?

Before processing user input, we must check:

• Required fields are not empty.
• Emails are in the correct format.
• Passwords meet security requirements.
• File uploads are within allowed size and type.

Laravel makes this easy with built-in validation features.

2. Basic Validation in Laravel 12

A. Using validate() in Controllers

The simplest way is to validate directly in a controller.

Example: Validating a Registration Form

use Illuminate\Http\Request;

public function register(Request $request)
{
    // Validate the request
    $validated = $request->validate([
        'name' => 'required|string|max:255',
        'email' => 'required|email|unique:users',
        'password' => 'required|min:8|confirmed',
    ]);

    // If validation passes, create user
    User::create($validated);

    return redirect('/dashboard')->with('success', 'Registration successful!');
}

Explanation of Rules:

❌ If validation fails, Laravel automatically redirects back with errors.

B. Displaying Validation Errors in Blade

Laravel stores errors in the $errors variable (available in Blade).

<form method="POST" action="/register">
    @csrf

    <!-- Name Field -->
    <div>
        <label>Name</label>
        <input type="text" name="name" value="{{ old('name') }}">
        @error('name')
            <span style="color: red;">{{ $message }}</span>
        @enderror
    </div>

    <!-- Email Field -->
    <div>
        <label>Email</label>
        <input type="email" name="email" value="{{ old('email') }}">
        @error('email')
            <span style="color: red;">{{ $message }}</span>
        @enderror
    </div>

    <!-- Password Field -->
    <div>
        <label>Password</label>
        <input type="password" name="password">
        @error('password')
            <span style="color: red;">{{ $message }}</span>
        @enderror
    </div>

    <!-- Confirm Password -->
    <div>
        <label>Confirm Password</label>
        <input type="password" name="password_confirmation">
    </div>

    <button type="submit">Register</button>
</form>

Key Points:

✔ old('field') repopulates form data after validation fails.
✔ @error('field') displays validation errors.

3. Advanced Validation: Form Request Classes

Instead of cluttering controllers, Laravel allows dedicated validation classes.

Step 1: Create a Form Request

php artisan make:request RegisterUserRequest

Step 2: Define Rules in rules() Method

public function rules()
{
    return [
        'name' => 'required|string|max:255',
        'email' => 'required|email|unique:users',
        'password' => 'required|min:8|confirmed',
    ];
}

Step 3: Use in Controller

public function register(RegisterUserRequest $request)
{
    // Validation passed automatically!
    User::create($request->validated());
    return redirect('/dashboard');
}

✅ Benefits:
✔ Cleaner controllers
✔ Reusable validation logic

4. Custom Validation Rules

Sometimes, built-in rules aren’t enough. Let’s create a custom rule.

Example: Check if a Username is "Admin" (Forbidden)

php artisan make:rule ForbiddenUsername

Now, edit app/Rules/ForbiddenUsername.php:

public function passes($attribute, $value)
{
    return strtolower($value) !== 'admin';
}

public function message()
{
    return 'The :attribute cannot be "admin".';
}

Using the Custom Rule

use App\Rules\ForbiddenUsername;

$request->validate([
    'username' => ['required', new ForbiddenUsername],
]);

5. Real-Time Validation (Optional with Livewire)

For a smoother UX, validate fields as the user types using Laravel Livewire.

Example: Instant Email Validation

use Livewire\Component;

class RegisterForm extends Component
{
    public $email;

    public function updatedEmail()
    {
        $this->validateOnly('email', [
            'email' => 'required|email|unique:users',
        ]);
    }

    public function render()
    {
        return view('livewire.register-form');
    }
}

Now, errors appear instantly without page reload!

6. Common Validation Rules Cheat Sheet

Conclusion

Laravel validations are easy yet powerful!

Key Takeaways:

✔ Use $request->validate() for quick checks.
✔ Form Request classes keep controllers clean.
✔ Custom rules handle unique business logic.
✔ Livewire enables real-time validation.

🚀 Now go ahead and secure your Laravel forms!