You can use the Circle API [sandbox environment](🔗) to exercise various types of card payment behaviors, such as authorization failure codes and address verification results.

To get your desired behavior:

  1. Use one of the test numbers listed below

  2. Choose a specific payment amount, CVV code, or address value

# Eligible Card Numbers

No Real Charges

The [sandbox environment](🔗) will authorize card payments made with any card number, but it will **never actually verify or charge the card**.

To make payments on the sandbox environment please use one of the provided test card numbers below, using other card numbers will return an error response.

Card numberCard provider

# Response Codes

To trigger specific response codes, use the corresponding amounts below when creating a payment. Any amount not specified in the table will return `Approved` (response code `00`).

AmountResponse codeDescription
5.01payment_failedPayment failed due to unspecified error
5.04card_not_honoredContact card issuer to query why payment failed
5.05payment_not_supported_by_issuerIssuer did not support the payment
5.07payment_not_fundedInsufficient funds in account to fund payment
5.19card_invalidInvalid card number
5.41card_limit_violatedExceeded amount or frequency limits
5.43payment_deniedPayment denied by Circle Risk Service or card processor risk controls
5.51payment_fraud_detectedPayment suspected of being associated with fraud
5.54credit_card_not_allowedIssuer did not support using a credit card for payment
5.57payment_stopped_by_issuerA stop has been placed on the payment or card
5.84card_account_ineligibleIneligible account associated with card

# CVV Verification

For more information on the card verification value (CVV) check and return values see the [verifying card details guide](🔗).

Setting the CVV to `000` or `999` will cause a CVV failure response.

# AVS Verification

For more information on the address verification service (AVS) check and the possible return codes see [verifying card details guide](🔗).

To trigger a particular AVS check result, set the address line 1 field to `Test_X`, where `X` is one of the available AVS return codes. The result defaults to AVS code `Y` otherwise.