Xident PHP SDK

Server-side PHP SDK for Xident age and identity verification. Zero external dependencies. Works with Laravel, Symfony, WordPress, and any PHP 8.1+ application.

Requirements

• PHP 8.1+
• cURL extension (bundled with PHP)
• JSON extension (bundled with PHP)

Installation

composer require xident-io/php-sdk

Without Composer: require_once '/path/to/xident-php/autoload.php';

Quick Start

use Xident\SDK\Client;

$xident = new Client(apiKey: $_ENV['XIDENT_SECRET_KEY']);

// 1. Create init token (your backend)
$session = $xident->verification()->init([
    'callback_url' => 'https://yoursite.com/verify-callback',
    'min_age'      => 18,
]);
// Redirect user to $session->verifyUrl

// 2. After user returns, verify server-side (NEVER trust URL params)
$result = $xident->verification()->getResult($token);

if ($result->isVerified()) {
    echo $result->ageBracket(); // 18
}

How It Works

1. Your backend calls POST /verify/v1/init with your secret key
2. SDK returns a token + verify URL. You redirect the user there.
3. User completes verification on verify.xident.io (liveness + age check)
4. User redirected back to your success_url with ?token=xxx
5. Your backend calls GET /verify/v1/result/{token} to get the result
6. You make the authorization decision based on the verified result

API Reference

Client

$xident = new \Xident\SDK\Client(
    apiKey:     'sk_live_xxx',            // Required
    baseUrl:    'https://api.xident.io',  // Optional (default)
    timeout:    30,                        // Optional seconds
    maxRetries: 3,                         // Optional (retries on 5xx)
);

verification()->init(params): InitResult

Parameter	Type	Required	Description
callback_url	string	Yes	HTTPS URL for callback (localhost OK for dev)
min_age	int	No	12, 15, 18, 21, or 25. Default: 18
success_url	string	No	Redirect on success
failed_url	string	No	Redirect on failure
user_id	string	No	Your internal user ID
theme	string	No	light, dark, auto
locale	string	No	en, de, es, fr, it, pt, nl, pl, tr, ar, ja
metadata	string	No	Custom JSON (max 1KB)

Returns: $result->token, $result->verifyUrl

verification()->getResult(token): SessionResult

Helpers: isVerified(), isFailed(), isPending(), isTerminal(), ageBracket(), method()

webhooks()->constructEvent(payload, signature, secret): array

Verify HMAC-SHA256 webhook signature and parse event.

$event = $xident->webhooks()->constructEvent(
    payload:   file_get_contents('php://input'),
    signature: $_SERVER['HTTP_X_XIDENT_SIGNATURE'],
    secret:    'whsec_xxx',
);
// $event['type'], $event['data']

Error Handling

use Xident\SDK\Exceptions\XidentException;
use Xident\SDK\Exceptions\AuthenticationException;
use Xident\SDK\Exceptions\NotFoundException;

try {
    $result = $xident->verification()->getResult($token);
} catch (AuthenticationException $e) {
    // 401 - Invalid API key
} catch (NotFoundException $e) {
    // 404 - Session not found
} catch (XidentException $e) {
    echo $e->getErrorCode();   // API error code
    echo $e->getRequestId();   // For support tickets
    echo $e->getHttpStatus();  // HTTP status
}

Exception hierarchy: AuthenticationException (401), ValidationException (400), NotFoundException (404), RateLimitException (429), ServerException (5xx), NetworkException (cURL errors).

Retry Behavior

Automatic retry with exponential backoff (1s, 2s, 4s) on 5xx and network errors only. Never retries 4xx.

Laravel Example

class VerificationController extends Controller
{
    public function start(Request $request)
    {
        $xident = new \Xident\SDK\Client(apiKey: config('services.xident.secret_key'));
        $session = $xident->verification()->init([
            'callback_url' => route('verify.callback'),
            'min_age' => 18,
            'user_id' => (string) $request->user()->id,
        ]);
        return redirect($session->verifyUrl);
    }

    public function callback(Request $request)
    {
        $xident = new \Xident\SDK\Client(apiKey: config('services.xident.secret_key'));
        $result = $xident->verification()->getResult($request->input('token'));
        if ($result->isVerified()) {
            $request->user()->update(['age_verified' => true]);
            return redirect()->route('dashboard');
        }
        return redirect()->route('verify.failed');
    }
}

See examples/ for Symfony, WordPress, and webhook examples.

Security

• Secret key: Never expose sk_* in frontend code
• TLS 1.2+: Enforced on all API calls
• Webhooks: Always verify signatures (hash_equals for timing-attack resistance)
• Verification tokens: Always re-verify server-side. Never trust URL params alone.
• SSRF: HTTP client does not follow redirects

Testing

composer test              # 96 tests, 200 assertions
composer test:coverage     # With HTML coverage report

Mock the client in your tests:

$transport = new \Xident\SDK\Tests\Helpers\MockTransport();
$transport->queueSuccess(['token' => 'xit_test', 'verify_url' => 'https://verify.xident.io?t=xit_test']);
$client = new \Xident\SDK\Client('sk_test_xxx', transport: $transport);

Links

• Try it live
• Documentation
• API Reference
• JavaScript SDK (client-side counterpart)
• Dashboard (get your API key)

License

MIT