What a test CVV is

A test CVV is a fake security code printed beside a fake card number that a payment processor publishes for its sandbox. The number and code route through a simulation layer, never the live card networks, so no money moves and no real account is touched. Square, Stripe, Adyen, and Braintree all ship these values so developers can confirm that a checkout form, token request, and decline handler behave as intended. A test CVV is not a credential for a live transaction, and a live card number does not belong in a sandbox.

Request declined: testing card data against Square

Our pick: Square sandbox test cards

Square wins for teams already building on the Square Web Payments SDK. The test values come from the same developer dashboard that issues sandbox credentials, so card entry, tokenization, and the Payments API response land in one place. Square publishes a short list rather than a broad catalog, which keeps the choice simple and keeps the test data current with the current API version.

square test cvv vs razorpay

Run a Square test payment

  1. Sign in to the Square developer dashboard and open the application you want to test.
  2. Switch the application credentials toggle from production to sandbox.
  3. Open the sandbox test card list and copy one card number with its matching CVV.
  4. Enter the number and CVV in your checkout form, and use an expiry date in the future.
  5. Submit the payment and confirm the token and the payment response in the API log.
  6. Repeat with each listed card until you have covered approval, decline, and error responses.

Alternatives worth testing against

Stripe test cards

Stripe runs the widest test set of the four. The 4242 series accepts any future expiry and any three-digit CVC, and a long list of decline numbers triggers specific error codes such as insufficient funds or a blocked card. Teams that need to exercise a dozen failure paths usually pick Stripe as the reference sandbox even when the production stack is Square.

square test cvv vs razorpay

Adyen test cards

Adyen lists test numbers by region and scheme, each with a fixed CVC. The regional split is useful when your checkout has to handle local card formats and localized error text, and the fixed CVC makes scripted test runs repeatable.

square test cvv vs razorpay

Braintree test cards

Braintree pairs test numbers with fixed CVVs and documents the exact response each one returns, including processor decline text. It is the cleanest option when you need to prove that your decline messaging matches what the processor sends.

How the options compare

  • Coverage: Stripe and Adyen list the most numbers; Square lists the fewest.
  • Decline simulation: Stripe and Braintree map numbers to named error codes.
  • Regional cards: Adyen leads, with test values grouped by country and scheme.
  • Setup cost: Square and Stripe issue sandbox keys in minutes with a free account.
  • Documentation: all four document test values, but Braintree explains the response per card.

Rules for safe sandbox testing

  • Use published test numbers only, and keep them inside sandbox mode.
  • Never place live cardholder data in a test environment, even for a moment.
  • Store sandbox keys in environment variables, not in committed source files.
  • Clear test customers and test transactions before you switch to production credentials.
  • Recheck the test card list after each API version upgrade, since values do change.