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Cross border payments with Bitcoin over Lightning

If you are building a cross border payments or multi-currency use case that relies upon Bitcoin settling "fast" on the lightning network, the proposedRate parameter here may be of interest. This only works in the case of standing orders where there is a "two-sided payment" such as this where the receiver generates a lightning invoice and a payer pays it.

When generating an invoice, you can propose a rate to execute a swap at for BTC/EUR specifically. This comes in handy when setting up a Standing Order and you want a fixed rate to be guaranteed when automatically converting BTC into EUR to payout via SEPA or SEPA Instant.

In such cases, you may pass in the Transfer of Funds Regulation (TFR) (or "Travel Rule") information to the best possible extent, containing the optional fields below -

VASP Information:

Names: 1-200 chars, alphanumeric with common business characters (&, -, ., parentheses)
Emails: Proper email validation with normalization and max 255 chars
Extra info: Max 500 chars

Originator/Beneficiary:

Names: 1-200 chars, letters only with spaces, hyphens, apostrophes, periods, commas
Account numbers: 1-100 chars, alphanumeric with hyphens
Address: 1-500 chars (more lenient for international addresses)
Country: Strictly 2-letter ISO country codes (e.g., US, GB, DE)
National ID type/number: Alphanumeric with hyphens, reasonable lengths
Customer number: Alphanumeric with hyphens
Date of birth: YYYY-MM-DD format validation
Place of birth: Letters with spaces, hyphens, commas
Amount: Numeric string with optional decimal (e.g., "100" or "100.50")
Currency: Strictly 3-letter ISO 4217 codes (e.g., USD, EUR, BTC)
Timestamp: ISO 8601 format (e.g., 2026-01-26T12:00:00Z)