Hosted checkout
What buyers see on /pay/{invoiceId} and how payment links differ from API invoices.
API invoice checkout
After POST /api/v1/invoices, redirect to checkout_url:
https://ulasend.com/pay/{invoice_id}The page shows amount + network, QR / deposit address, optional coin picker (filtered by your Accepted coins), optional buy-with-card, and live status updates.
Buy with card defaults to USDC on Base unless the buyer has already selected a different coin. Details: Buy with card.
Payment links
Dashboard / API payment links (/l/pl_…) are reusable. If dynamic amount is enabled, your frontend can pass this cart's usd_amount when starting checkout — same idea as creating an API invoice per order.