Quickstart
Quickstart
Accept your first crypto payment in under 5 minutes.
This guide walks you through the minimal integration needed to create an invoice and handle the resulting webhook when a customer pays.
Prerequisites
- A Billium merchant account
- A secret API key (
sk_...) created in the dashboard under Settings → Developer → API keys. See Authentication for the difference between secret (sk_*) and public (pk_*) keys. - Your merchant ID (
mer_...), shown on the same page - A publicly reachable HTTPS URL for webhooks (use ngrok for local development)
Steps
Create an invoice — call the API from your backend with the amount and the crypto you want to accept.
Redirect the customer — send them to the checkout URL returned by the invoice.
Handle the webhook — Billium calls your endpoint when the invoice status changes.