Card Testing

<script type="module">
  const mod = await import(
    'https://cdn.shieldlabs.ai/snippet.js?publicKey=YOUR_PUBLIC_KEY'
  );
  // The browser does NOT compute the Risk Score. Keep result.requestID:
  // join key to the webhook.
  mod.forceCheckAuthenticatedUser('a1b2c3d4hasheduserid', {
    onInitialized: (result) => {
      if (result.status !== 'initialized') return;
      document.getElementById('shieldlabs-request-id').value = result.requestID;
    },
  });
</script>

<form id="checkout-form" method="POST" action="/api/pay">
  <input type="hidden" id="shieldlabs-request-id" name="shieldlabsRequestId" />
  <!-- payment fields -->
  <button type="submit">Pay</button>
</form>

app.post('/api/pay', async (req, res) => {
  const { shieldlabsRequestId } = req.body;
  const userHid = req.user?.hashedId; // signed-in buyers; absent on a guest checkout

  // The identification for this attempt: webhook `data`, or a History row
  // mapped to the same field names.
  const risk = await waitForScore(shieldlabsRequestId, 2000);

  // No identification is not the same as "clean". Hold rather than charge blind.
  if (!risk) {
    return res.status(202).json({ status: 'review', reason: 'no_identification' });
  }
  // A signed-in buyer's identification must be theirs. Guests send "anonymous".
  if (userHid && risk.user_hid !== userHid) {
    return res.status(202).json({ status: 'review', reason: 'identification_mismatch' });
  }
  // The 999 rate-limit marker, or no usable Device ID: route to review.
  if (risk.risk_score > 100 || !risk.device_id || risk.device_id === NIL_DEVICE) {
    return res.status(202).json({ status: 'review', reason: 'unverified_device' });
  }

  // YOUR velocity: count this attempt on the Device ID, and on the Local IP
  // when it was captured (empty when not captured, null on the History fallback).
  const attempts = await bumpAttemptCount('device:' + risk.device_id);  // your store
  const localIp = risk.local_ip?.ip;
  const networkAttempts = localIp ? await bumpAttemptCount('local_ip:' + localIp) : 0;

  if (attempts > YOUR_ATTEMPT_LIMIT || networkAttempts > YOUR_NETWORK_LIMIT) {
    return res.status(202).json({ status: 'step_up', reason: 'card_testing' });
  }

  // First clean attempts pass to the risk signal check below, which answers
  // step_up or allow; charge on allow in your own flow.
  return decideOnSignals(risk, res);
});

// Inside /api/pay, after the guard and before decideOnSignals(risk, res).
// accountsBehindDevice is a shared helper: the distinct accounts seen on one
// device in its newest 100 identifications. Guest checks carry "anonymous",
// which is not an account.
// A failed History read is unverified: hold the payment for review.
const accounts = await accountsBehindDevice(risk.device_id).catch(() => null);
if (accounts === null) {
  return res.status(202).json({ status: 'review', reason: 'history_unavailable' });
}
if (accounts > YOUR_ACCOUNTS_PER_DEVICE_LIMIT) {
  return res.status(202).json({ status: 'review', reason: 'many_accounts_on_device' });
}