Billium Developer Docs

Explore our API references, SDKs, and guides for accepting crypto payments in any app.

Get started

Popular quickstarts

Create your first invoice

Call the API to generate an invoice with an expected amount, currency, and customer details.

Handle the payment

Receive the webhook when confirmations settle and mark the order as paid in your database.

Authenticate your requests

Sign every API call with your merchant API key and keep it out of client-side code.

Build with Billium

Use Billium's API, SDK, and dashboard to power crypto payments in your product.

REST API

A REST API that covers every Billium primitive

Create invoices, track payments, and monitor confirmations through a predictable, idempotent HTTP API.

Read the docs

POST /invoices

# Create an invoice
curl -X POST \
  https://api.billium.to/api/v1/merchants/merchant/$MER_ID/invoices \
  -H "x-api-key: sk_..." \
  -H "content-type: application/json" \
  -d '{"name":"Order #1234","rawAmount":99.99,"currency":"USD"}'

201 Created

{
  "id": "inv_Lx8vG3hBqa…",
  "status": "AWAITING_PAYMENT",
  "rawAmount": "99.99",
  "endAmount": "99.99",
  "currency": "USD",
  "expiresAt": "2026-04-13T18:30:00Z"
}