A Square test card is a publicly documented card number that works only in Square's sandbox (test) environment to simulate a payment without moving real money. Developers use these numbers to test checkouts, refunds, and error handling before an app goes live. The most widely used example is the Visa number 4111 1111 1111 1111, entered with any future expiration date and any three digit code.
What is a Square test card used for?
Test cards let you exercise the full payment flow without touching a real bank account. You can confirm that your checkout collects card data correctly, that your server reads the response object, and that your interface shows the right message to a customer. Because no issuer is involved, the charge is simulated end to end.
Which test card numbers does Square document?
Square lists numbers for each major brand in its developer documentation. Commonly published examples include the following.
- Visa: 4111 1111 1111 1111
- Mastercard: 5105 1051 0510 5100
- American Express: 3782 822463 10005
- Discover: 6011 1111 1111 1117
- JCB: 3569 9900 1009 5841
Square also documents cards that trigger specific outcomes, such as a generic decline, insufficient funds, a card verification value mismatch, and a postal code mismatch. Card numbers and scenario behavior can change, so confirm the current values on the official testing page before you run a suite.
Do test cards accept any code and any expiration date?
For a basic approval, the security code and expiration date only need correct formatting: three digits for most brands, four for American Express, and a date in the future. Nothing is verified against an issuer, because there is no issuer. Some failure scenarios do expect a specific value to produce the error you want, so read the notes for each card.
Do Square test cards work in production?
No. Test card numbers are declined by live card networks, and Square blocks them in production. A test card can only produce a simulated authorization inside the sandbox.
How do you use a test card in the Square sandbox?
- Create a Square developer account and open an application in the Developer Dashboard.
- Switch the application to sandbox mode and copy the sandbox access token into your test configuration.
- Enter one documented test card number in your test checkout, with any cardholder name and a future expiration date.
- Compare the response with the expected result, then repeat with a decline card to check your error handling.
Test card numbers compared with real card data
A test card number belongs to no person, cannot be charged, and carries no value. Real card numbers are sensitive authentication data. PCI DSS forbids storing the card verification value after a transaction is authorized, and using another person's card number without permission is card fraud under federal law.
Frequently asked questions
Is a Square test card the same thing as a CVV?
No. A test card is a full card number reserved for sandbox testing, while a CVV is the three or four digit verification code printed on a real card. Test numbers do not need a genuine code, and a real card should never be used for testing.
Can you test refunds and recurring payments with a Square test card?
Yes. A sandbox payment can be refunded or voided, and you can save a test card on file for a test customer to simulate subscription charges. This lets you verify your refund logic and your renewal logic without processing live money.
Where do you find the official list of Square test cards?
The official list sits in Square's developer documentation under testing and sandbox. Use that page rather than a copied list, because numbers and expected outcomes can be updated at any time.