Developers · Payment API
Full control over every payment, one REST call away
A clean REST API to create and manage payments, refunds and payouts — with server SDKs, idempotency and webhooks. Build exactly the flow you want.
What it does
Built to drop in
REST + server SDKs
A predictable REST API with SDKs for Node, Python and more — build any flow.
3-D Secure 2 built in
Strong Customer Authentication and fraud screening handled for you.
Idempotent & webhooks
Safe retries with idempotency keys; a signed event for every state change.
Sandbox keys
Test the whole flow with sandbox keys before you go live.
How it works
Three steps to live
01
Get your keys
Grab sandbox keys and go live when ready.
02
Create a payment
One call — cards, wallets, local rails or crypto.
03
Handle the webhook
React to a signed event; reconcile against your account.
payments.js
import { Klas } from "@1klas/node"
const klas = new Klas(process.env.KLAS_KEY)
const payment = await klas.payments.create({
amount: 4900, currency: "EUR",
method: "card", settle_to: "acct_multi"
}, { idempotencyKey: orderId }) // safe to retry
Better together
Pairs with the rest of the stack
Start building
From first call to money in your account
Grab sandbox keys, build the flow you want, and settle straight to your regulated 1klas account.