Initiates a transfer to move funds to a destination address via a specified payment rail.
Pass your API key as a Bearer token: Authorization: Bearer ld_live_...
The customer ID initiating the transfer
Transfer amount as a decimal string
Destination currency code
Payment rail for the destination (e.g. "ach", "wire", "polygon")
Destination address (counterparty ID, wallet address, etc.)
Source currency (defaults to "usdc")
Your own reference ID for idempotency or tracking