What a localization CVV test covers

A localization CVV test checks that your payment form accepts, formats, and validates the card security code for every locale and card brand you support. The variables look small, but they break checkouts: digit count, field label, input masking, mobile keyboard type, and the wording of error messages in the active language. Run the test in your payment processor's sandbox with published test cards. Live card data has no place in a QA pass.

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Prerequisites

• A sandbox or test merchant account
• Test card numbers for each brand, taken from your processor's documentation
• A staging build with a working locale switcher
• A list of the locales and payment methods your checkout supports

Procedure

1. Write down every locale in scope and the card brands each one accepts.
2. Switch the storefront to the first locale.
3. Open the payment step and confirm the label follows the brand naming used in that market, such as CVV, CVC, CVV2, or CID.
4. Enter a 3-digit code from a sandbox Visa test card.
5. Confirm the field accepts the third digit and blocks a fourth.
6. Repeat with a sandbox American Express card and confirm the field accepts 4 digits.
7. Paste a code that has leading and trailing spaces and check the field trims them.
8. Open the same form on a phone and confirm the numeric keypad appears instead of the full keyboard.
9. Submit a code that does not match the sandbox card and read the error message.
10. Confirm the error message is written in the active locale, not the base language.
11. Enter a code with a leading zero, such as 007, and confirm the zero is not stripped.
12. Inspect the browser network tab and the server logs to confirm the code is not written to analytics or log files.
13. Repeat the locale and brand checks for every remaining locale.
14. Record pass or fail for each locale and brand combination.

What to record

Keep one row per locale and card brand. Capture the expected digit count, the label text that rendered, the keyboard type on mobile, the exact localized error string, and the result. A column for screenshots saves time when a translator or designer needs to see the defect. Store the results in a shared sheet so the matrix survives the next redesign.

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Common failure modes

• Input maxlength hard-coded to 3, which rejects American Express codes
• Brand label left in English on a translated page
• Error strings pulled from a base translation file with no locale override
• CVV value sent to an analytics event or an application log
• Right-to-left or CJK layouts that clip the input or shift the mask
• Autofill hints that populate the wrong field on mobile

Scope note

This procedure applies to payment forms you own or build, tested with sandbox credentials and vendor-issued test cards. Do not enter live card numbers, and do not test card data that belongs to anyone else.

Test CVV Localization Guide