Square test cards

Use these details to try payments in a Square 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.

Square’s sandbox accepts only these test values, not real cards. Connecting a sandbox account works slightly differently from a live one: see the sandbox steps in Connecting Square.

Where these details come from

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

How to choose a test result

• Square’s sandbox refuses real cards and accepts only its own test values.
• The card number sets the result. For the error triggers, type the CVV, expiry date or postcode into the Square card form in the checkout: the postcode goes in the postcode box of that same card form. Our Square connection doesn’t take card numbers in an API request, so test cards can only be tried through the checkout.
• The SCA (3D Secure) cards only show their result when we ask Square to verify the payment. We do this on every online card payment while Use Square Risk Manager for 3D Secure is off in the Square connection settings here (see Connecting Square). Leave it off to test them. With it on, your Square Risk Manager rule decides. Payments taken over the phone (MOTO) are never verified, so the SCA cards can’t be tested that way.
• ACH needs Enable ACH switched on in the Square connection settings here, and ACH enabled on the Square account. The setting appears only when the Square account takes USD. Then sign in to Plaid’s test bank when the checkout asks you to connect a bank.

Cards

Use any future expiry month and year, and the CVV shown. Payments in USD, CAD and GBP need a valid postcode; payments in Japan don’t use a postcode.

Successful payments

Card	Number	Notes
Visa	4111 1111 1111 1111	CVV 111
Mastercard	5105 1051 0510 5100	CVV 111
American Express	3400 000000 00009	CVV 1111
Discover	6011 0000 0000 0004	CVV 111
Diners Club	3000 0000 0000 04	CVV 111
JCB	3569 9900 1009 5841	CVV 111
UnionPay	6222 9888 1234 0000	CVV 123

Declines and errors

Number or trigger	Result
4000 0000 0000 0002	Declined
4000 0000 0000 0010	Declined when the card is saved for later payments (card on file)
Expiry date 01/40	Declined: expiry date incorrect

3D Secure

Square calls this SCA (strong customer authentication). In the sandbox, Square asks for verification in every region, not only where it is required. Where a card shows a challenge, enter the verification code 123456; it stands in for the code a bank would send by text message.

Number	Result
4800 0000 0000 0004	Visa. No challenge
5222 2200 0000 0005	Mastercard. No challenge
6011 0000 0020 1016	Discover (EU). No challenge
3569 9900 0000 0017	JCB. No challenge
4310 0000 0020 1019	Visa (EU). Challenge: enter code 123456
5248 4800 0021 0026	Mastercard. Challenge: enter code 123456
5500 0000 0020 1016	Mastercard (EU). Challenge: enter code 123456
3700 000002 01014	American Express (EU), CVV 1111. Challenge: enter code 123456
3569 9900 0000 0009	JCB. Challenge: enter code 123456
4811 1100 0000 0008	Visa. No challenge, and verification fails

Use CVV 111 unless a row says otherwise. Square supports testing with JCB cards only for sellers in Australia, Canada and Japan.

Address and CVC checks

Value	Result
CVV 911	Declined: CVV incorrect
Postcode 99999	Declined: postcode incorrect

ACH (US bank accounts)

Square’s sandbox takes ACH payments through Plaid’s test bank sign-in rather than a routing and account number. When asked to sign in to the bank, use the user name user_good and the password pass_good.

These values come from Plaid and can change.

In person (Square terminal)

Square’s sandbox doesn’t support testing card-present payments, so in-person payments on a Square terminal can’t be tried in the sandbox.