Locking checkout fields

By default, users can change the amount, currency, and payment method on the checkout page. You can lock any of these fields to prevent changes, giving you more control over the order flow.

fixedAmount

When set to true, the user cannot change the order amount on the checkout page. The amount you specified (quoteCurrencyAmount or baseCurrencyAmount) is locked.

When to use: you have already shown the user a price in your UI (e.g. from a quote) and want to ensure they pay exactly that amount.

{
  "quoteCurrencyAmount": 50,
  "fixedAmount": true
}

fixedCurrency

When set to true, the user cannot change the cryptocurrency on the checkout page. The baseCurrency you specified is locked.

When to use: your platform only supports specific currencies, or the user has already selected a currency in your UI and switching would invalidate other data (e.g. the wallet address).

{
  "baseCurrency": "BTC",
  "fixedCurrency": true
}

fixedPaymentMethod

When set to true, the user cannot change the payment method on the checkout page. The paymentMethod you specified is locked.

When to use: you have already determined the best payment method for the user (e.g. based on their country) and want to streamline the checkout experience.

{
  "paymentMethod": "iDeal",
  "fixedPaymentMethod": true
}

Combining locked fields

You can lock multiple fields at once. For example, to create a fully pre-configured checkout where the user only needs to confirm:

{
  "baseCurrency": "BTC",
  "quoteCurrency": "EUR",
  "paymentMethod": "iDeal",
  "quoteCurrencyAmount": 50,
  "walletAddress": "bc1...",
  "fixedAmount": true,
  "fixedCurrency": true,
  "fixedPaymentMethod": true
}

This is useful when you have already collected all preferences in your own UI and want the BTC Direct checkout to act as a confirmation step only.