Add localization to your Flow integration
Last updated: October 8, 2025
By default, the language displayed on Flow is derived from the locale set in the payment-session request.
Alternatively, you can use the locale configuration option to manually set the language in the CheckoutWebComponent. For example:
The following left-to-right (LTR) and right-to-left (RTL) languages are supported:
| Language | Code | Language type |
|---|---|---|
Arabic |
| RTL |
Chinese (China) |
| LTR |
Chinese (Hong Kong) |
| LTR |
Chinese (Taiwan) |
| LTR |
Danish |
| LTR |
Dutch (Netherlands) |
| LTR |
English (United Kingdom) |
| LTR |
Filipino |
| LTR |
Finnish |
| LTR |
French |
| LTR |
German |
| LTR |
Greek |
| LTR |
Hindi |
| LTR |
Indonesian |
| LTR |
Italian |
| LTR |
Japanese |
| LTR |
Korean |
| LTR |
Malay |
| LTR |
Norwegian Bokmål |
| LTR |
Portuguese |
| LTR |
Spanish |
| LTR |
Swedish |
| LTR |
Thai |
| LTR |
Vietnamese |
| LTR |
You can customize the default text translation for a specific language by providing your own strings.
- Create a
translationsobject and specify thelocalefor which you want to provide custom translations. Within the locale object, include the translation keys you want to customize, along with their values. For example:
- Pass the
translationsobject when you create the instance ofCheckoutWebComponents.
You can customize the following default text:
| Translation key | Default text | Description |
|---|---|---|
| Bank Account | The label for the bank account option. |
| Cancel | The label for the cancel button. |
| Change | The label for the change button. |
| Continue | The label for the continue button. |
| Loading | Message shown when loading additional information. |
| Card | The label for the the card option. |
| Cardholder name | The label for the cardholder name input. |
| Card number | The label for the the card number input. |
| Your card number is incomplete | Error message shown when the card number is incomplete. |
| {CARD} not supported | Error message shown when the card number comes from an unsupported card scheme. |
| Expiry date | The label for the card expiry date input. |
| Your card's expiry date is in the past | Error message shown when the card expiry date is invalid. |
| MM | Message describing the format for card expiry month input. |
| YY | Message describing the format for card expiry year input. |
| Choose your preferred scheme | The label for the preferred scheme selection. |
| "Your card offers two schemes, and you can select the one you prefer. Otherwise, the default choice applies." | Message prompting the customer to select their preferred scheme. |
| Security code | The label for the the card security code (CVV) input. |
| Your card's security code is incomplete | Error message shown when the security code (CVV) is incomplete. |
| CVV | Message describing the format for card security code input. |
| Save card details for future purchases | The label for the option to store card details for future purchases. |
| Remember this card | The call to action message to remember card details for future use. |
| Phone number not registered | Error message shown when the phone number is not registered. |
| Edit | The label for the edit button. |
| Email address | The label for the email input. |
| Must be a valid email | Error message shown when the customer provides an invalid email. |
| Placeholder message shown in the empty email input field. | |
| Full name | The label for the full name input. |
| Jordan Smith | Placeholder message shown in the empty full name input field. |
| Must be greater than | Error message shown when the customer inputs a value shorter than the required length. |
| Holder first name | The label for the account holder first name input. |
| Jordan | Placeholder message shown in the empty account holder first name input field. |
| Holder last name | The label for the account holder last name input. |
| Smith | Placeholder message shown in the empty account holder last name input field. |
| Must be less than | Error message shown when the customer inputs a value longer than the required length. |
| National ID | The label for the national ID input. |
| National ID is invalid | Error message shown when the national ID is invalid. |
| 30063412345 | Placeholder message shown in the empty national ID input field. |
| Country code | The label for the phone country code input. |
| Phone number | The label for the phone number input. |
| Enter your phone number | The label for the phone number entry. |
| Must be a valid phone number | Error message shown when the phone number is invalid. |
| This field is required | Error message shown when the customer leaves a required field blank. |
| Show Klarna options | The label for the display Klarna options button. |
| Enter your verification code | The label for the verification code entry. |
| Enter the verification code sent to | The call to action message to capture the verification code sent to the customer’s contact details. |
| Enter the verification code sent to your email | The call to action message to capture the verification code sent to the customer’s email |
| Enter the verification code sent via SMS | The call to action message to capture the verification code sent to the customer’s phone via SMS. |
| Enter the verification code sent via WhatsApp | The call to action message to capture the verification code sent to the customer’s phone via WhatsApp. |
| Send code via email | The call to action message to send verification code via email. |
| Incorrect verification code. Try again. | Error message shown when the verification code is invalid. |
| The code has expired. Request a new one. | Error message shown when the verification code expires. |
| Verification code must be | Error message shown when the submitted verification code has an invalid amount of digits. |
| Send code via SMS | The call to action message to send verification code via SMS. |
| We'll send a verification code to | Message shown to confirm the customer’s contact details where the verification code will be sent to. |
| Failed to verify OTP | Error message shown when the customer verification fails. |
| Max resends reached | Error message shown after reaching the maximum resend limit for the verification code. |
| Max retries reached | Error message shown after reaching the maximum number of verification code retries. |
| Resend a code in | Message shown when the customer needs to wait before verification code can be resent. |
| Resend code | The call to action message to resend verification code. |
| Didn’t receive the code? | Message shown to the customer if they want their verification code to be resent. |
| Send to email instead | The call to action message to resend verification code via email. |
| Send to SMS instead | The call to action message to resend verification code via SMS. |
| Send verification email | The call to action message to send verification code via email. |
| Send verification SMS | The call to action message to send verification code via SMS. |
| Sending verification SMS | Message shown when the verification code is being sent via SMS. |
| Confirm | The label for the confirm button. |
| Confirming | Message shown when confirming details. |
| Pay | The call to action shown on the pay button. |
| Payment complete | Message shown when the payment is completed. |
| Payment processing | Message shown while the payment is processing. |
| Pay with | The payment method specific call to action shown on the pay button. |
| After clicking on Pay, you are redirected to finalize your payment | Message shown before the customer is redirected to complete their payment. |
| Approve payment on the | The call to action message to approve payment in the mobile application of the payment method. |
| I have canceled this payment | The label for the button confirming that the customer cancelled the payment. |
| I have approved this payment | The label for the button confirming that the customer approved the payment. |
| Card not supported | Error message shown when the customer provides a card that is not supported. |
| Incorrect details – try again or use another payment method | Error message shown when the customer provides invalid payment details. |
| Try another payment method | Error message shown when the |
| Payment declined – try another payment method | Error message shown when your account is not configured for the payment method you are trying to process. |
| Not enough funds – try another payment method | Error message shown when the customer does not hold sufficient funds to complete the transaction with their chosen payment method. |
| Payment cancelled | Error message shown when the payment is cancelled. |
| Payment expired | Error message shown when the payment request expires. |
| Payment declined – try again or use another payment method | Fallback message shown when the chosen payment method declines the transaction. |
| Payment successful | Message shown when the payment is successful. |
| Something went wrong. Try another payment method. | Error message shown after failing to load the payment method. |
| Creditor | The label for the SEPA Direct Debit creditor name. |
| Creditor ID | The label for the SEPA Direct Debit creditor ID. |
| IBAN | The label for the the International Bank Account Number (IBAN) input. |
| Please enter a valid IBAN. Your IBAN should start with two letters and be 22 characters long | Error message shown when the International Bank Account Number (IBAN) is invalid. |
| AB12 1234 1234 1234 1234 12 | Placeholder message shown in the empty International Bank Account Number (IBAN) input. |
| Saved cards | The label for the stored card options. |
| Use a new card | The label for the use new card option displayed next to stored card options. |
| Loading your saved cards | Message shown when loading stored card options. |
| Other payment methods | The label for other payment method options when stored cards are available. |
| Default | The label for the default option. |
| Expired | The label for an expired option. |
To add support for locales and languages not natively supported by Flow, provide the locale as an object of key-value pairs within the same translations object you used for custom translations. For example, to add support for US English (en-US):
Information
If you are missing a translation for the locale you provide, Flow attempts to fall back to the language of the specified locale. If the locale language is not supported, Flow falls back to en.