Guest checkout fraud: How to stop repeat offenders

Say you’re shopping online for some new dancing shoes. You find a great store, browse their products, and spot the perfect pair to spiff up your next night out. As you go to checkout, the website demands you create a new account. Did you know that 26% of people will abandon their cart at this point just to avoid creating a new account?!

No wonder so many online stores let you buy those bedazzled go-go boots with guest checkout! It cuts out the fluff, speeds up the process, and doesn’t ask customers for more info than needed to get their products delivered.

Unfortunately, what’s great for legitimate shoppers can become a free pass for fraudsters. In this article, we’ll break down the perks and pitfalls of guest checkout and how you can stop fraudsters from taking advantage of your platform even when your customers are anonymous.

What is guest checkout fraud?

Many e-commerce sites offer a guest checkout option that skips account creation and only asks for the essentials like payment and shipping info. This is great for privacy-minded or hurried shoppers, but it’s also a bonus for fraudsters. Unlike account-based checkouts, an anonymous checkout lacks any persistent identifiers, making it harder to link suspicious activity across transactions. With the minimal and often fake information provided, fraud can run unchecked.

How guest checkout makes e-commerce fraud easier

Unfortunately, when it comes to online shopping, there is no shortage of ways to commit fraud. Most of these center around exploiting payment systems and transactions with unauthorized or deceptive tactics. Guest checkout, while great for conversions, makes some of this fraud harder to catch.

Consider one common example: stolen credit card fraud. Guest checkout gives fraudsters the perfect disguise, leaving merchants in the dark without account history or customer profiles. This makes it nearly impossible to stop repeat offenders or catch red flags like subtle changes in shipping details or unusual purchasing patterns across multiple transactions.

Friendly fraud, or chargeback fraud, is another challenge. For example, legitimate customers with buyer's remorse may dispute charges after a purchase, claiming they didn’t authorize them (even though they absolutely did). Without records of account activity or order history, merchants struggle to provide evidence to fight these claims.

Guest checkout can also open the door to policy abuse, such as promo or coupon abuse. Fraudsters can pose as different individuals to take advantage of deals and loyalty programs. Without accounts to link their actions, it becomes challenging to monitor their activity and enforce promo policies effectively.

Even if you did require customers to create accounts, what’s stopping fraudsters from simply making new ones? Not much. Using tools like VPNs to mask their location or browser tampering to manipulate their digital appearance, fraudsters can look like entirely new customers with every transaction, making it nearly impossible to connect their actions or catch them in the act.

A better way to do guest checkout

At the heart of these payment fraud challenges is the anonymity that comes with offering your customers guest checkout. So, if guest checkout makes fraud easier, why bother having it? Simple — customers love it. It’s faster, lets them skip handing over extra personal information, and potentially avoids getting those annoying marketing emails. That convenience is often the difference between a completed purchase and an abandoned cart.

Without accounts, you need a way to link transactions and detect patterns to spot returning offenders and prevent fraud. But how can you still keep your conversions high and not piss off your legitimate users? This is where device intelligence comes in. It works behind the scenes to analyze a user’s device, detect risky characteristics, and recognize them when they return.

With reliable device identification, merchants can flag and identify offenders and stop them before they have a chance to strike again. Instead of relying solely on account data or easily manipulated signals like cookies or IP addresses, device intelligence provides a more persistent and accurate way to catch fraudulent behavior while keeping the checkout experience smooth for legitimate customers.

Fingerprint’s industry-leading device intelligence

When it comes to device and browser identification, Fingerprint is the leading solution for accuracy and reliability. Fingerprint assigns a unique visitor ID to each browser or device that visits your site or mobile app, enabling you to recognize them, even if they never signed up for an account. You can even recognize them if they clear cookies, change their IP address, or browse in incognito mode. This level of precision is critical for stopping repeat payment fraud offenders who use these tactics to try and mask their identity.

But Fingerprint goes beyond just visitor identification. Our Smart Signals provide additional insights into potentially risky behavior like VPN detection, browser tampering detection, and app cloning. With these signals, merchants can make real-time decisions on how to handle risky behavior, whether that means blocking transactions, requiring additional verification, or flagging them for manual review. Together, this data gives businesses the insight they need to uncover risky visitors and stop fraudsters who might otherwise slip through unnoticed.

How to detect past offenders in your guest checkout

To begin to thwart anonymous fraudsters with Fingerprint, you’ll first need an account and your API keys. You can sign up for a free trial and then find your API keys in the Fingerprint dashboard. Once you have them, you’re ready to make visitor identification requests and learn more about your anonymous users.

The example below walks you through integrating Fingerprint into a checkout flow. With this setup, you can identify repeat offenders and take the appropriate actions based on your own fraud strategy.

Note: If you’re following along, make sure to disable any ad blockers in your browser. These examples use our CDN for easy setup, but for production, you should protect the Fingerprint client from being blocked with a proxy integration.

1. Make a visitor identification request

When a user checks out as a guest, you’ll want to request identification from Fingerprint. Start by loading the client agent as soon as the page loads. This ensures it’s ready when needed, such as when the user clicks a “Confirm Order” button. The example below uses basic JavaScript, but we also offer SDKs for popular frameworks and languages for both web and mobile development.

// Initialize the Fingerprint client agent as soon as possible
const fpPromise = import("https://fpjscdn.net/v3/YOUR_PUBLIC_API_KEY").then(
  (FingerprintJS) => FingerprintJS.load()
);

async function processOrder(orderDetails) {
  // Request identification data when you need it
  const fp = await fpPromise;
  const result = await fp.get();
  const { requestId, sealedResult } = result;

  // Include the requestId and/or sealedResult with the order details
  const orderPayload = {
    ...orderDetails,
    requestId,
    sealedResult
  };

  const requestOptions = {
    method: "POST",
    body: JSON.stringify(orderPayload),
    headers: {
      "Content-Type": "application/json",
      Accept: "application/json",
    },
  };

  // Send the order payload to your server
  const response = await fetch("/api/process-order", requestOptions);

  // ... additional order logic
}

When you call get(), Fingerprint returns a JSON object with details about the visitor, including their unique visitorId, a requestId for this specific identification request, and a confidence.score indicating the certainty of the identification.

The requestId is used for retrieving full identification details, such as Smart Signals. This should be handled securely on the server to prevent client-side tampering. You can use it to fetch details from our Server API, or enable Sealed Client Results to receive the entire identification payload as an encrypted object directly from the get() request. This eliminates the need for a second request, reducing latency. If enabled, the response will include a sealedResult property containing the encrypted data, which you can decrypt on your server. We recommend this approach for better performance and will use it below.

2. Send identification details to your server

Once you’ve passed the result from the identification request to your server, you’ll need to decrypt it. Then you can then store this information alongside any details for the order. All of the following steps should be done securely on your server. Begin by installing your preferred version of the Fingerprint Server API library — here, we’re using the Node SDK.

npm install @fingerprintjs/fingerprintjs-pro-server-api

Then, retrieve and decrypt the identification event to access the full details.

const {
  unsealEventsResponse,
} = require("@fingerprintjs/fingerprintjs-pro-server-api");

const { sealedResult } = request.body;
const decryptionKey = "YOUR_ENCRYPTION_KEY";

// Decrypt the identification event
const unsealedData = await unsealEventsResponse(
  Buffer.from(sealedResult, "base64"),
  [
    {
      key: Buffer.from(decryptionKey, "base64"),
      algorithm: "aes-256-gcm",
    },
  ]
);

To see an example of the data provided in the identification event, you can view our demo playground and see the details for your own device.

3. Detect suspicious behavior

Even without a history of fraudulent orders, Fingerprint Smart Signals provide insights into visitor characteristics. Depending on your use case and traffic patterns, certain signals may indicate risk and warrant additional friction. You can pull these signals from the identification event and take action accordingly.

For example, it’s very unlikely that you want to allow your checkout process to be accessed by a bot. Fingerprint’s bot detection can identify automated activity, helping you prevent bots from making fraudulent automated purchases.

// Prevent bots from making purchases
if (unsealedData.products.botd.data.bot.result !== "notDetected") {
  return {
    success: false,
    error: "Order failed.",
  };
}

4. Store and retrieve visitor IDs when processing orders

Next we want to retrieve the visitorId from the Fingerprint identification event. Then, query your database for past orders linked to that visitorId and check for any fraud flags. Based on the results, you can decide whether to block the transaction, require additional verification, or any variety of actions. Fingerprint is flexible; we provide you the data but you make the decisions.

If no fraud is detected, continue processing the order and store the visitorId with the order details to be able to link future orders. If the order is later found to be fraudulent — such as when a stolen credit card is used — update the record with a fraud flag so it can be recognized in the future.

// Count how many times this visitor ID has been linked to fraudulent transactions
const [rows] = await db.execute(
  `SELECT COUNT(*) AS fraud_count FROM orders
  WHERE visitor_id = ? AND status = 'fraudulent'`,
  [visitorId]
);

if (rows[0].fraud_count > 0) {
  // Fraudster detected – require extra verification or block transaction
  return {
    success: false,
    message:
      "Order flagged for review. Additional verification required.",
  };
}

// Store the visitor ID with order details. (Example just for brevity)
await db.execute(
  `INSERT INTO orders (visitor_id, order_id, amount, items, status) 
    VALUES (?, ?, ?, ?, 'pending')`,
  [visitorId, orderId, amount, items]
);

return { success: true, message: "Order received." };

By linking the Fingerprint visitor ID to your orders and your fraud flagging, you have effectively made an offenders list that you can use to protect your checkouts. Even if the fraudsters try to hide behind VPNs or cloned applications, Fingerprint will still recognize them and help you block their future fraud attempts.

Stop repeat fraudsters without sacrificing guest checkout

Fraudsters thrive on anonymity, and guest checkout is one of their favorite ways to slip past traditional fraud detection. Without accounts to link transactions, spotting repeat offenders is tough — but not impossible. Fingerprint bridges this gap, with industry-leading accuracy in recognizing visitors even if they clear cookies, switch IPs, or browse in incognito mode.

With this visibility, you can block high-risk transactions, require extra verification, or flag suspicious orders for review when you notice a fraudster. And the best part? It all happens behind the scenes — no friction, no extra steps, just smarter fraud prevention that keeps guest checkouts smooth.

Check out our demo or reach out to our team to learn how Fingerprint can help you stop fraudsters without slowing down real customers.