Install the Widget

Add SilentShield to your website with a single line of code. The widget automatically detects forms and starts protecting them.

Basic Integration

Add this code snippet before the closing </body> tag of your website:

<script src="https://api.silentshield.io/client.js?k=YOUR_API_KEY" crossorigin="anonymous" defer></script>

What Happens Automatically

The widget detects all forms on the page
Behavior analysis starts in the background (invisible to users)
A CAPTCHA appears only when suspicious behavior is detected
A verification nonce is injected into forms before submission

Server-Side Verification (Recommended)

After a form is submitted, validate the nonce on your server to confirm the submission is from a human.

POST https://api.silentshield.io/api/v1/captcha/verify-nonce

X-Api-Key: YOUR_API_KEY

PHPphp

<?php
$nonce = $_POST['behavior_nonce'] ?? '';
$ch = curl_init('https://api.silentshield.io/api/v1/captcha/verify-nonce');
curl_setopt_array($ch, [
    CURLOPT_POST => true,
    CURLOPT_HTTPHEADER => [
        'Content-Type: application/json',
        'X-Api-Key: ' . $apiKey,
    ],
    CURLOPT_POSTFIELDS => json_encode(['nonce' => $nonce]),
    CURLOPT_RETURNTRANSFER => true,
]);
$result = json_decode(curl_exec($ch), true);
curl_close($ch);

if ($result['verdict'] === 'bot') {
    http_response_code(403);
    die('Bot detected');
}

Node.jsjavascript

const response = await fetch('https://api.silentshield.io/api/v1/captcha/verify-nonce', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'X-Api-Key': process.env.SILENTSHIELD_API_KEY,
  },
  body: JSON.stringify({ nonce: req.body.behavior_nonce }),
});
const data = await response.json();
if (data.verdict === 'bot') {
  return res.status(403).json({ error: 'Bot detected' });
}

Testing

Add ?silentshield-debug to your URL to activate the debug overlay. It shows the current behavior score, verdict, and active features in real time.

Next: Verify your domain