A payment link is a hosted checkout page. You set the title, amount and currency, share the link, and watch the payment move from pending to succeeded. A QR code does the same in person.
- Sign in to the merchant dashboard.
- Create a payment link or a QR code and set what it is for and how much.
- Share the link, or show the code. Your customer pays on the hosted page.
Everything you can do in the dashboard you can also do through the API. Test it first with a sandbox key, which moves no real money: see Sandbox and live API keys.