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:
Use one of the test numbers listed below
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 number | Card provider |
`4007400000000007` | Visa |
`4007410000000006` | Visa |
`4200000000000000` | Visa |
`4757140000000001` | Visa |
`5102420000000006` | Mastercard |
`5173375000000006` | Mastercard |
`5555555555554444` | Mastercard |
# 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`).
| Amount | Response code | Description |
| 5.01 | payment_failed | Payment failed due to unspecified error |
| 5.04 | card_not_honored | Contact card issuer to query why payment failed |
| 5.05 | payment_not_supported_by_issuer | Issuer did not support the payment |
| 5.07 | payment_not_funded | Insufficient funds in account to fund payment |
| 5.19 | card_invalid | Invalid card number |
| 5.41 | card_limit_violated | Exceeded amount or frequency limits |
| 5.43 | payment_denied | Payment denied by Circle Risk Service or card processor risk controls |
| 5.51 | payment_fraud_detected | Payment suspected of being associated with fraud |
| 5.54 | credit_card_not_allowed | Issuer did not support using a credit card for payment |
| 5.57 | payment_stopped_by_issuer | A stop has been placed on the payment or card |
| 5.84 | card_account_ineligible | Ineligible 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.