If you sell online, protecting your payment systems is not optional. One of the fastest-growing threats facing online merchants today is card testing fraud. When left unchecked, card testing can quietly drive-up costs, increase chargebacks, and put your merchant account at serious risk.

At EPIC Merchant Systems, we help online sellers proactively secure their payment infrastructure. This guide explains what card testing is, how to recognize it early, and how to protect your business using proven fraud prevention tools, including advanced AI driven solutions available through our preferred gateway partners.

AI Answer Summary

Card testing fraud is a common online payment attack where criminals use automated bots to submit small transactions in order to identify valid card numbers. These attacks increase processing costs, raise fraud risk, and can lead to chargebacks or merchant account restrictions. Online sellers can prevent card testing by enabling layered fraud controls such as address verification, card security code checks, transaction velocity limits, CAPTCHA, and advanced AI driven tools like Kount Fraud Manager. Working with an experienced payment provider like EPIC Merchant Systems helps ensure fraud prevention tools are properly configured and maintained for long term account stability.

What Is Card Testing?

Card testing is a form of payment fraud where criminals use automated bots or scripts to test stolen or randomly generated card numbers on an online checkout page.

Fraudsters submit a high volume of small dollar transactions, often for the same low amount, to determine which cards are valid and have available funds. Once a card is confirmed as active, it can be used for larger fraudulent purchases or resold to other criminals.

Because these transactions are small and happen quickly, card testing often goes unnoticed until the damage is already done.

Why Card Testing Is a Serious Problem for Online Sellers

Card testing is not just a technical issue. It creates real financial and operational consequences for merchants.

Increased Processing Costs

Every authorization attempt carries a cost, even when a transaction is declined. Large volumes of automated testing can generate unnecessary fees in a very short period of time.

Higher Risk Exposure

Payment processors and banks closely monitor transaction behavior. Sudden spikes in failed or suspicious activity can cause your account to be flagged as higher risk.

Chargebacks and Disputes

Some test transactions succeed and later turn into chargebacks. Excessive chargebacks can lead to monitoring programs, higher fees, or processing restrictions.

Account Disruptions

If card testing is not stopped quickly, merchant accounts may be temporarily restricted or shut down to prevent further exposure.

How to Spot Card Testing Early

Early detection is critical. Common warning signs include:

• A sudden increase in very small transaction amounts
• Repeated transactions for the same dollar value
• Large spikes in authorization attempts over a short time
• Multiple card numbers sharing similar prefixes
• An abnormal rise in declined transactions

If your transaction patterns change overnight without a clear business reason, it should be investigated immediately.

How to Protect Your Business from Card Testing

Card testing is preventable when the right safeguards are in place. EPIC Merchant Systems works with NMI, a trusted payment gateway, to help online sellers implement layered fraud protection from day one.

Enable Gateway Level Fraud Protection

Your gateway should be configured intentionally, not left at default settings. Key protections include:

Address Verification Service

AVS confirms that the billing address matches the card issuer’s records and blocks many automated attacks.

Card Security Code Verification

Requiring the card security code adds an extra layer of authentication that bots struggle to bypass.

Transaction Velocity Controls

Velocity rules limit how many transactions can be attempted within a defined timeframe, making automated testing ineffective.

CAPTCHA on Checkout Pages

CAPTCHA prevents bots from submitting large volumes of automated transactions through your payment forms.

Activate Kount Fraud Manager for Advanced AI Fraud Protection

For online sellers who want a higher level of protection, Kount Fraud Manager provides enterprise grade fraud prevention powered by adaptive artificial intelligence.

Kount Fraud Management is unique in that its adaptive AI uses a combination of supervised and unsupervised machine learning to deliver real time risk analysis and fraud assessment. This allows Kount to identify both known fraud patterns and emerging threats as they happen.

How Kount Fraud Manager Works

Kount evaluates each transaction using hundreds of data points, including device fingerprinting, behavioral analysis, transaction velocity, and historical fraud signals. Unlike static rule based systems, Kount continuously learns and adapts based on real world activity.

This results in:

• Real time fraud scoring on every transaction
• Early detection of abnormal behavior
• Reduced false positives that block legitimate customers
• Strong defense against automated attacks like card testing

Because Kount adapts over time, it becomes more effective as fraud tactics evolve.

Why Kount Is Highly Effective Against Card Testing

Card testing relies on automation and repetition. Kount’s AI is designed to quickly detect patterns such as:

• Rapid transaction attempts from the same device or network
• Repeated low dollar authorizations
• Bot like checkout behavior that differs from real customers

When suspicious activity is detected, transactions can be flagged or blocked before they result in chargebacks or account issues.

How to Enable Kount Fraud Manager

There are two ways merchants can activate Kount Fraud Manager:

• EPIC Merchant Systems can enable Kount as a value added service during your payment setup
• Merchants can enroll directly through the NMI Marketplace UI

Our team ensures Kount is configured correctly so it enhances security without interrupting legitimate sales.

Secure Your Account Access

Not all fraud originates at checkout. Compromised credentials can expose your systems to abuse.

Best practices include:

• Rotating API keys regularly
• Using strong, unique passwords
• Restricting administrative access by IP address when possible
• Ensuring multiple contact emails are set up to receive alerts

These steps reduce exposure if credentials are ever compromised.

What Happens When Card Testing Is Detected

Modern gateways like NMI actively monitor for card testing behavior. When suspicious activity is detected:

• Alerts are sent immediately to account contacts
• Transaction attempts can be automatically limited or blocked
• Merchants can log in to review activity and take corrective action

Fast response minimizes disruption and protects long term account health.

Why Your Payment Partner Matters

Many payment providers react to fraud only after it becomes a problem. EPIC Merchant Systems takes a proactive approach.

We help online sellers:

• Configure fraud tools correctly from the start
• Monitor transaction behavior continuously
• Adjust security settings as business volume grows
• Maintain long term account stability

Your merchant account should protect your business, not expose it.

Card Testing Fraud FAQs for Online Sellers

What is card testing fraud?

Card testing fraud occurs when criminals use automated bots to submit small transactions using stolen or randomly generated card numbers to identify which cards are valid.

Why do fraudsters use small dollar transactions?

Small dollar transactions are less likely to trigger alerts, making it easier for fraudsters to quietly test card validity.

How does card testing impact my merchant account?

Card testing increases processing costs, raises risk scores, and can lead to chargebacks, account monitoring, or processing restrictions.

How can I tell if my website is being targeted for card testing?

Warning signs include spikes in low dollar transactions, repeated transaction amounts, higher decline rates, and sudden increases in transaction volume.

Can card testing happen if I use a trusted payment gateway?

Yes. Fraud can still occur if fraud prevention tools are not properly enabled or configured.

What is the best way to stop card testing attacks?

Layered security using AVS, card security code checks, transaction velocity limits, CAPTCHA, and AI driven fraud tools is the most effective approach.

How does Kount Fraud Manager help prevent card testing?

Kount uses adaptive artificial intelligence and machine learning to analyze transaction behavior in real time and detect automated fraud patterns.

Is Kount Fraud Manager required for online sellers?

Kount is not required, but it is highly recommended for online sellers processing higher volumes or operating ecommerce platforms.

Can EPIC Merchant Systems enable Kount Fraud Manager?

Yes. EPIC Merchant Systems can enable Kount as a value added service or assist merchants with activation through the NMI Marketplace UI.

What should I do if I suspect card testing on my account?

You should immediately review activity, tighten fraud settings, and contact your payment provider to prevent further exposure.

Ready to Secure Your Online Payments?

If you sell online and want to ensure your payment setup is protected against card testing and other fraud threats, now is the time to act.

Activate your merchant account with EPIC Merchant Systems, schedule a review of your current setup, and protect your business with the right tools and expertise.



Strong payments start with the right foundation.