Multi-Accounting

<script type="module">
  const mod = await import(
    'https://cdn.shieldlabs.ai/snippet.js?publicKey=YOUR_PUBLIC_KEY'
  );
  // Pass the hashed account id, never a raw email or user id.
  // The callback hands you the requestID to correlate with the score.
  mod.checkAuthenticatedUser('8a9f-hashed-account-id', (ip, requestID) => {
    document.getElementById('shield-request-id').value = requestID;
  });
</script>

<form method="POST" action="/api/account-action">
  <input type="hidden" id="shield-request-id" name="shieldRequestId" />
  <button type="submit">Continue</button>
</form>

{
  "request_id": "13f84f05-7c2a-4e9b-9f1d-2a6b8c0e4d11",
  "device_id": "5eb7fd5c-2a1b-4c3d-9e8f-7a6b5c4d3e2f",
  "visitor_id": "161dfbad-8e7f-4a6b-9c5d-0e1f2a3b4c5d",
  "user_hid": "8a9f...hashed-account-id",
  "public_ip": { "ip": "203.0.113.42", "country": "US" },
  "local_ip": { "ip": "192.168.1.24", "country": "US" },
  "risk_score": 20,
        "signals": [
    { "name": "Proxy", "weight": 10 },
    { "name": "Datacenter IP", "weight": 10 }
  ],
  "detection_flags": { "proxy": true, "datacenter_ip": true, "ip_mismatch": true },
  "observed_at": "2026-06-16T18:00:45Z"
}

app.post('/api/account-action', async (req, res) => {
  const { accountId, shieldRequestId } = req.body;

  // 1. Read the scored result for this session (cache, then History fallback).
  const shield = await waitForScore(shieldRequestId, 2000);
  const score    = shield?.score ?? 0;        // 0–100; default 0 if not yet in
  const deviceId = shield?.device_id;         // the durable linking key

  // 2. The all-zero DeviceID is "no device" (JS-disabled / blocked), not a new
  //    machine. Skip the link count for it and decide on the score alone.
  const NIL = '00000000-0000-0000-0000-000000000000';
  const usableDevice = deviceId && deviceId !== NIL;

  // 3. Count the distinct accounts that have appeared on this one device.
  //    An anonymous visit stores the literal "anonymous" — drop it before
  //    counting. History caps at 100 rows per page, so for a high-traffic
  //    device track the device->account set in your own store (see note).
  let accountsOnDevice = 1;
  if (usableDevice) {
    const rows = await shieldHistory('device_id', deviceId, 100);
    const accounts = rows
      .map((r) => r.user_hid)
      .filter((h) => h && h !== 'anonymous');
    accountsOnDevice = new Set(accounts).size;
  }

  // 4. YOUR code owns the verdict. Branch on the count and the band, never on
  //    a signal label string. Tune YOUR_ACCOUNT_LIMIT against your own traffic.
  if (usableDevice && accountsOnDevice >= YOUR_ACCOUNT_LIMIT) {
    return res.status(200).json({ requireVerification: true, reason: 'many_accounts_one_device' });
  }
  if (score >= 60) {
    return res.status(200).json({ requireVerification: true, reason: 'anonymity' });
  }

  return allow(req, res);
});

curl "https://account.shieldlabs.ai/api/v1/history/device_id/5eb7fd5c-2a1b-4c3d-9e8f-7a6b5c4d3e2f?limit=100" \
  -H "Authorization: Bearer sec_your_private_api_key"