You can block a specific card number from transactions directly in your Dashboard or using the Stripe API.

Block a card from the Dashboard

There are two ways to block a card number in the Dashboard:

1. From the Payments section of your dashboard, click on the charge from the customer whose card you want to block, click Refund in the top right corner, and select Fraudulent ad the refund reason. This will automatically add the payment’s card and email to your blocklist.
2. If you have Radar For Fraud Teams: navigate to your Radar blocklist, where you can view, add, and delete card numbers and email addresses manually.

Block a card using the Stripe API

You can block a card in the API two ways:

1. Create a refund request and include reason='fraudulent'.
2. Add charges to your Radar blocklist by making a charge update request with fraud_details.user_report='fraudulent'.