Use case
Payment fraud: spot risky checkouts before you charge
Payment fraud rarely looks like one bad transaction. It looks like one device trying many cards, a checkout from a hosting network, or a tampered browser. FingerPrint Checker tags each checkout event with signals about the device and the network, so your payment rules can use them alongside what your card processor tells you.
The threat
Card testing runs many small attempts, often from one device that keeps changing IPs. Stolen-card orders come from hosting networks, proxies and browsers built to hide the buyer. Repeat chargebacks come from the same person under new accounts.
What the signals show
- Velocity: many different IPs or accounts from one device in minutes, which is the shape of card testing.
- Proxy, datacenter, Tor and blocklist: checkouts that come from networks real shoppers rarely use.
- Bot and tampering: scripted checkouts and browsers altered to hide the buyer.
- The same device on an account that already had a chargeback, found through the visitor ID and your linked ID.
How to add it
Identify the device at checkout and tag the event with your order or user id. Your backend reads the event with your secret key and applies your own rules before capturing the payment, or holds the order for review. Signals are evidence, so use them to route cases to review rather than as the only reason to refuse a customer.
Hold a risky checkout for review
// Backend, after the browser sent the event id with the checkout
const event = await getEvent(eventId); // GET /v1/events?linkedId=order_123 with your secret key
const s = event.signals;
const velocity = s?.velocity?.distinctIp['5m'] ?? null; // null is unknown, not zero
const risky = s === null || s.bot.result === 'bad' || s.proxy.result === true || (velocity !== null && velocity > 3);
return risky ? holdForReview(order) : capturePayment(order); // your rulesFrequently asked questions
Does this replace my payment processor’s fraud tools?
No. It adds device and network context that your processor does not see. Use both.
Will a customer on a VPN be refused?
Only if your rules say so. A VPN signal is evidence, and many honest customers use one. Most teams send those orders to review.
Try it on your own sign-up flow
Every new account gets 2,000 free checks. No card required.