How to Validate Emails in Laravel with Mailchk

Laravel's validation system is one of its best features, and adding external email validation fits naturally into the framework. This guide shows you how to integrate Mailchk using a custom validation rule, a reusable service class, and form request validation.

Step 1: Create a Service Class

// app/Services/EmailValidationService.php
<?php
namespace App\Services;

use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Cache;

class EmailValidationService
{
    public function validate(string $email): array
    {
        return Cache::remember(
            'email_validation:' . md5($email),
            now()->addHours(24),
            fn () => $this->callApi($email)
        );
    }

    private function callApi(string $email): array
    {
        $response = Http::withHeaders([
            'X-API-Key' => config('services.mailchk.key'),
        ])->post('https://api.mailchk.io/v1/check', [
            'email' => $email,
        ]);

        if ($response->failed()) {
            return ['valid' => true, 'disposable' => false];
        }
        return $response->json();
    }
}

Step 2: Configuration

// .env
MAILCHK_API_KEY=your-api-key-here

// config/services.php
'mailchk' => ['key' => env('MAILCHK_API_KEY')],

Step 3: Custom Validation Rule

// app/Rules/ValidEmail.php
<?php
namespace App\Rules;

use App\Services\EmailValidationService;
use Closure;
use Illuminate\Contracts\Validation\ValidationRule;

class ValidEmail implements ValidationRule
{
    public function __construct(
        private bool $blockDisposable = true,
        private bool $blockFreeEmail = false
    ) {}

    public function validate(string $attribute, mixed $value, Closure $fail): void
    {
        $result = app(EmailValidationService::class)->validate($value);

        if (!$result['valid']) {
            $fail('Please enter a valid email address.');
            return;
        }
        if ($this->blockDisposable && ($result['disposable'] ?? false)) {
            $fail('Disposable email addresses are not allowed.');
        }
        if ($this->blockFreeEmail && ($result['free_email'] ?? false)) {
            $fail('Please use your work email address.');
        }
    }
}

Step 4: Use in Form Requests

// app/Http/Requests/SignupRequest.php
public function rules(): array
{
    return [
        'name'  => ['required', 'string', 'max:255'],
        'email' => ['required', 'email', 'unique:users', new ValidEmail],
        'password' => ['required', 'min:8', 'confirmed'],
    ];
}

// Or inline in a controller:
$request->validate([
    'email' => ['required', 'email', new ValidEmail],
]);

Handling Typo Suggestions

$result = app(EmailValidationService::class)->validate($email);

if ($result['did_you_mean'] ?? null) {
    return back()->with('email_suggestion', $result['did_you_mean']);
}

// Blade template:
@if (session('email_suggestion'))
  <p class="text-amber-600">Did you mean {{ session('email_suggestion') }}?</p>
@endif

Best Practices

• Fail open — if the API is unreachable, allow the signup. Validate asynchronously later.
• Cache aggressively — same email validated during retries shouldn't cost extra calls.
• Queue for bulk imports — dispatch validation jobs rather than blocking the import process.
• Show typo suggestions — did_you_mean converts better than a hard rejection.

Getting Started

Get your free API key at mailchk.io/signup. 200 validations/month free, sub-50ms response time.