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Square Sandbox Test Cards

Square sandbox cards, SCA (3DS) cards and the CVV/postal/expiry values that force errors.

Tool inputs stay in your browser · optional AI search sends your query

Good to know: Error values: CVV 911, postal code 99999, expiry 01/40.

How to use it (step by step)

  1. 1Fill in the boxes: “Search (brand, country, scenario)”, “Show”, “Show numbers”. Example numbers are already there so you can see how it works; replace them with yours.
  2. 2The result updates instantly as you type (on a phone it is below the boxes).
  3. 3The bold line is the main answer. Tap Copy next to any value to copy it.

Words to know

CVV / CVC
The 3-digit code on the back of a card (4 digits on the front for Amex). It proves the person paying has the card in hand.
Test / sandbox mode
A practice version of a payment system. You can “pay” with test cards to try your checkout, but no real money moves.
3D Secure (3DS)
The extra step where your bank asks you to confirm a payment (an OTP or app approval). It protects against stolen cards.
Expiry date
The month and year printed on a card (MM/YY). The card works until the last day of that month.

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