Advanced fraud tools

The Stripe Issuing advanced fraud tools help you identify and prevent transaction fraud through API signals and tooling. This guide helps you understand how to use these signals and features to drive down transaction fraud while minimizing the impact on legitimate transactions.

Getting started with advanced fraud tooling

Advanced fraud tools provides resources that you can incorporate into decision making for Issuing authorizations and to prevent unauthorized use. Learn more about real time authorizations.

Using advanced fraud tools allows you to:

• Receive signals assessing several fraud vectors on every authorization, allowing you to make more informed authorization approval and decline decisions.
• Receive notifications that an issued card has been compromised, allowing you to proactively cancel and replace high risk cards.
• Trigger SMS-based fraud challenges on any authorization, driving down fraudulent activity while mitigating the impact to legitimate transaction activity.

Use signals for your authorization logic

As a first step, we recommend back-testing your authorization activity and past transaction fraud against the Stripe API signals to determine the optimal approve and decline thresholds to set for your portfolio.

When setting thresholds, set them for one of three outcomes, depending on the needs of your business:

• Approval rate maximization: Best if you prefer to approve more authorizations, even if it means more transaction fraud.
• Minimize fraud: Best if you’re trying to keep fraud to a minimum, even if it means good transactions are more likely to be declined.
• Balance of approval rate and fraud reduction: Best if you want a blend of the previous two options.

In most cases, fraud prevention and approval rate maximization are inversely related, but you might identify thresholds where you can apply both at the same time, depending on your portfolio composition. If you’re a new user without much history to backtest, see our recommended thresholds to start. We recommend refining these over time based on your fraud outcomes to layer in additional signals or adjust the thresholds based on performance.

You can also test API behavior by simulating authorizations with specific fraud signals in sandbox environments through either the Issuing dashboard, or using the API.

To compare your past activity with Stripe API signals, start by identifying transactions where a fraud dispute was filed, defined as having an evidence.reason of fraudulent. Then, compare that set of transactions to the set of transactions flagged by each signal. The amount of overlap between them indicates how likely a signal is to predict future fraud disputes.

Make sure to analyze a representative sample of recent transactions, but consider that disputes can take several weeks to report. We recommend looking only at transactions that occurred within the last 6 months, but not within the last 60 days.

For example, select a 90-day period ending 60 days ago. Within that period, compare the set of authorizations scored as risk_level = high to the set of transactions that resulted in a fraud dispute. If that signal flagged 90% of transactions that resulted in a dispute, but only a small number of transactions that didn’t, then it’s probably a reliable indicator for you. Alternatively, if that signal flagged only 5% of actually disputed transactions, then it probably isn’t very reliable for you.

When defining your authorization logic, implement rules that accurately prevent fraudulent disputes but have limited impact on legitimate authorizations. Aim for a precision of ~10%, meaning that at least 1 in 10 authorizations declined by your logic are actually fraudulent.

Identify and replace compromised cards

Advanced fraud tools notify you through the Cards API when Stripe suspects an issued card has been compromised, making it more likely to drive unauthorized use in the future. We recommend automatically canceling and reissuing cards when this occurs. Learn more about card replacement.

Send SMS-based fraud challenges in elevated risk scenarios

Even with advanced fraud tools API signals, it might not always be clear whether to approve or reject an authorization. For example:

• Rejecting a cardholder authorization might leave them without recourse on an important purchase.
• Cardholders do regularly engage in legitimate spend activity that might look anomalous (for example, a business trip abroad).
• The authorization looks legitimate but the user is newer to your platform and requires additional scrutiny.

Fraud challenges allow you to conduct additional verification on authorizations while mitigating the impact on good card spend. When triggered, fraud challenges decline an authorization and send an SMS to a cardholder’s phone number and asks the them to verify they recognize the authorization.

• Unless a fraudulent actor has access to the phone number on file, they won’t be able to complete this step, stopping the fraud vector.
• If the SMS fraud challenge is successfully delivered, a legitimate cardholder will be able to complete the prompt, allowing them to retry the authorization and get through on a second authorization attempt. This reduces the risk that the cardholder gets stranded at the point of sale, unable to make an important purchase.

Learn more about fraud challenges.

Advanced fraud tools feature set

Fraud challenges

Fraud challenges provide you with the ability to request additional, SMS-based verification in situations you prefer not to outright decline potentially risky authorizations.

False positive declines can occur in fraud protection. To allow cardholders to override potential false-positive declines and limit disruption, you can trigger SMS-based verification.

SMS verification works as an override option to a decline. For cardholders, the process looks like this:

1. Attempt an authorization, but receive a fraud-related decline.
2. Successfully complete a fraud challenge by replying to an SMS, sent to the cardholder’s phone number on file with Stripe.
3. Try the authorization again and receive approval.

If you enable fraud challenges, Stripe automatically triggers SMS verification for authorizations that we consider to be high risk.

If the cardholder successfully completes the verification within 60 minutes, the business is allow-listed on that card for 7 days. Subsequent authorizations during that time won’t encounter fraud-related declines.

Learn more about the fraud challenge flow.

Authorization signals

During authorization, we provide a comprehensive set of signals that you can use to make informed approve or decline decisions in real-time webhook responses.

Fraud risk assessment

Request access if you’re interested in our fraud risk assessment.

Merchant dispute risk

Receive detailed risk assessments of the acquiring merchant, or seller, involved in an authorization.

Make informed decisions based on risk level

If you have data on an acquiring merchant’s risk level and dispute likelihood, you can make more informed decisions about approving authorizations. Stripe makes that assessment by evaluating all of the acquiring transaction activity for a business on Stripe Issuing, including data such as its historical dispute rate.

Merchant dispute risk provides the dispute rate and risk for a given acquiring merchant across all Stripe Issuing transaction activity. The higher the value, the more frequently the merchant’s past authorizations have resulted in a dispute. This value can be useful when deciding whether to approve the first purchase at a particular acquiring merchant by one of your cards.

Determine the risk level

To determine the risk level, examine the merchant dispute risk hash. The following example demonstrates how to use each value.

Example responses

A normal risk authorization, where only 5% of past authorizations from this merchant have resulted in a dispute:

{
  "id": "iauth_1CmMk2IyNTgGDVfzFKlCm0gU",
  "object": "issuing.authorization",
  // ...
  "risk_assessment": {
    "merchant_dispute_risk": {
      "risk_level": "normal",
      "dispute_rate": 5
    }
  }
}

A high-risk authorization, where 57% of past authorizations from this merchant have resulted in a dispute:

{
  "id": "iauth_1CmMk2IyNTgGDVfzFKlCm0gU",
  "object": "issuing.authorization",
  // ...
  "risk_assessment": {
    "merchant_dispute_risk": {
      "risk_level": "high",
      "dispute_rate": 57
    }
  }
}

Learn more about merchant dispute risk.

Card testing risk

Card testing is a prevalent form of fraud where fraudulent actors test stolen card numbers or cycle through primary account numbers (PANs) until they find a valid one. They use this valid PAN at a business with weak verification controls. To counteract this, Stripe assesses the likelihood of your involvement in a card testing attack, takes action on your behalf, and notifies you through the API about the severity of the incident. Additionally, we assess if any cards might have been compromised during the attack.

Make informed decisions based on card testing risk

Stripe automatically intervenes in the most obvious card testing scenarios. We offer a balanced approach in normal-risk situations to avoid being overly conservative. These cases require careful consideration of various factors, including the authorization and cardholder details. As a result, we recommend the careful evaluation of all relevant considerations before making a decision on whether to block an authorization.

We assess card testing risk by, among other things, evaluating the frequency and intensity of “card does not exist” declines associated with a specific bank identification number (BIN) or business. These declines are the most definitive significant indicator because they often exhibit a noticeable increase in speed and frequency compared to regular card declines.

Determine card testing risk

To determine card testing risk, examine the card testing risk hash. The following example demonstrates how to use each value. We also provide the following fields:

• Invalid account number decline rate: The percentage of declines because of a card number not existing in the past hour, taking place at the same business. Higher rates correspond to a greater probability of card testing activity, meaning fraudulent actors might be attempting different card number combinations to guess a correct one.
• Invalid credentials decline rate: The percentage of declines because of incorrect verification data (such as CVV or expiry) in the past hour, taking place at the same business. Higher rates correspond to a greater probability of fraudulent actors attempting to use valid card credentials at businesses with verification requirements. This value spiking means fraudulent actors likely have a valid PAN but can’t supply valid verification data.

Example responses

A normal risk authorization:

{
  "id": "iauth_1CmMk2IyNTgGDVfzFKlCm0gU",
  "object": "issuing.authorization",
  // ...
  "risk_assessment": {
    "card_testing_risk": {
      "risk_level": "normal",
      "invalid_account_number_decline_rate_past_hour": 2,
      "invalid_credentials_decline_rate_past_hour": 1
    }
  }
}

A high-risk authorization:

{
  "id": "iauth_1CmMk2IyNTgGDVfzFKlCm0gU",
  "object": "issuing.authorization",
  // ...
  "risk_assessment": {
    "card_testing_risk": {
      "risk_level": "highest",
      "invalid_account_number_decline_rate_past_hour": 79,
      "invalid_credentials_decline_rate_past_hour": 83
    }
  }
}

Learn more about card testing risk.

Fraud disputability likelihood

Stripe’s fraud disputability assessment evaluates whether an authorization can be disputed in the event of fraud.

Make informed decisions based on authorization disputability

Knowing whether or not you can dispute an authorization in the event of fraud at the time of authorization allows you to make informed decisions. For example, consider an authorization that’s otherwise classified as “normal risk”:

• If you know that you can dispute the authorization if fraud occurs, you can approve it.
• If you know that you can’t dispute the authorization (if fraud occurs), you can opt to decline it or trigger a fraud challenge for additional verification.

Stripe assesses the disputability likelihood by comparing the characteristics of the authorization (such as whether 3DS was used or if the card was present with a chip). We make this assessment against network rules for disputes to proactively determine what would happen in the event of a dispute.

Determine the likelihood that a dispute can be filed

To determine the disputability likelihood of an authorization in the event of fraud, examine the fraud disputability likelihood field. This field populates with various enums that inform you about whether you can dispute the authorization. We label every authorization as very_likely, neutral, very_unlikely, or unknown:

• When authorizations receive a score of very_likely, it’s highly probable that disputes filed based on these authorizations are accepted by the card network. The card network rarely rejects very_likely authorization disputes. When they do, it’s typically because of exceptional circumstances. These circumstances might include a card filing a fraud dispute for the second time or exceeding the allowable number of disputes for a card within a specific timeframe defined by Visa or MasterCard.
• When authorizations receive a score of very_unlikely, disputes are almost always automatically rejected by the card network.
• When authorizations receive a score of neutral, Stripe assesses that the dispute outcome depends on various factors. Historically, these disputes are more likely to be accepted by the card network. However, this behavior might change at any given point.

Most issuing activity is classified as very_likely, but how often each of these values populate depends on the composition of your issuing activity. For example, online authorizations are more likely have very_likely values than in person authorizations. Learn more about fraud disputability likelihood.

Compromised card alerting

Stripe notifies you through the API when we believe a card might have been compromised. This helps you know when to cancel and reissue a card, file disputes, or notify a cardholder.

Prevent subsequent abuse and initiate cardholder communications

Canceling a card suspected to be compromised can help you prevent future fraudulent use of PANs that have been compromised. You can use these indicators to initiate communications and a reissuance workflow for cardholders. If Stripe observes that a card has been compromised in a risk event, we flag the card as compromised.

Mitigate risk and take action

When Stripe determines that a card number or PAN has likely been compromised in one or more of the following risk events, Stripe marks the card as compromised.

• A card testing attack where a successful authorization took place
• The cardholder verified through SMS that they didn’t attempt a past authorization on the card
• A fraud dispute has been filed on the card in the past
• The PAN was found in a dark web search

When a risk event takes place, we update the fraud warning hash to notify you. The started_at value corresponds to the date that the risk event took place. If a subsequent risk event takes place, both values update to reflect the most recent event.

If either value is populated, we recommend contacting the cardholder, canceling the card, and issuing a new one. This mitigates the risk of subsequent unauthorized use on what a fraudulent actor likely assumes is a valid PAN that they can make purchases with.

Using advanced fraud tools through the Stripe Dashboard

If you want to use the authorization signals of advanced fraud tools for fraud prevention through the Stripe Dashboard, Stripe offers a rules engine. To request access, please contact Stripe using the contact form at Stripe Support.