NMI test cards

Use these details to try payments in an NMI sandbox (test) account. They work only in the sandbox: never use them in live, and never put real card or bank details into a sandbox.

NMI sandbox accounts are available through NMI’s developer site, guide.nmi.com. An NMI account can also be switched into test mode, where NMI approves every valid card without charging it. Declines are triggered by the payment amount.

Where these details come from

These are NMI’s test details, not ours. They were copied from NMI’s Testing Methods page on 19 October 2026, and were correct on that date as far as that page shows. NMI can change or withdraw them at any time, and we can’t confirm that they work. Check NMI’s page for the current details, and ask NMI if one doesn’t behave as described.

How to choose a test result

• Any valid card below is approved, and the amount sets declines: enter an amount below 1.00 at the checkout (for example 0.50) to be declined. We send the amount to NMI as you type it (Testing Methods).
• Use an NMI sandbox account rather than an account in test mode: NMI says test mode approves every valid card, so the decline trigger doesn’t apply there (Testing Methods).
• For the address check, switch on Require address (AVS) in the NMI connection settings so that checkout asks for a billing address, then enter 888 as the first line of the address and 77777 as the ZIP code. Enter CVC 999 in the checkout’s CVC field (Testing Methods).
• For 3D Secure, switch on Enable 3DS and add your NMI public key in the connection settings (see Connecting NMI). Checkout then also asks for the customer’s name, email and billing address.
• For ACH, switch on Enable ACH in the connection settings and on your NMI account.

Cards

Use the expiry date 10/29, NMI’s test expiry date.

Successful payments

Card	Number	Notes
Visa	4111 1111 1111 1111
Mastercard	5431 1111 1111 1111
American Express	3411 111111 11111
Discover	6011 0009 9130 0009
Diners Club	3020 5252 4899 26
JCB	3541 9635 9457 2595
Maestro	6799 9901 0000 0000 019

Declines and errors

Number or trigger	Result
Amount less than 1.00	Declined

3D Secure

These are for NMI sandbox accounts. NMI’s 3D Secure testing page lists a different set of cards for accounts in test mode.

Number	Result
4111 1111 1111 1111 (Visa), 5431 1111 1111 1111 (Mastercard), 3411 111111 11111 (American Express)	Not enrolled: no authentication takes place
4100 0000 0000 0100 (Visa)	No challenge: authenticated
5100 0000 0000 0107 (Mastercard)	No challenge: authenticated
3400 000000 00108 (American Express)	No challenge: authenticated
6440 0000 0000 0104 (Discover)	No challenge: authenticated
4100 0000 0000 5000 (Visa)	Challenge: enter 12345 to pass, any other code to fail, or close the challenge to cancel
5100 0000 0000 5007 (Mastercard)	Challenge: enter 12345 to pass, any other code to fail, or close the challenge to cancel
3400 000000 05008 (American Express)	Challenge: enter 12345 to pass, any other code to fail, or close the challenge to cancel
6440 0000 0000 5004 (Discover)	Challenge: enter 12345 to pass, any other code to fail, or close the challenge to cancel

Address and CVC checks

Value	Result
Address line 1 888 and ZIP code 77777	Address check matches
CVC 999	CVC matches

ACH (US bank accounts)

Routing number	Account number	Result
490000018	24413815	NMI’s test bank account. NMI doesn’t list ACH decline or return triggers
123123123	123123123 (savings)	Approved. Used in our own tests