S-interio Checkout API
The Checkout API lets you create a secure payment page to charge your customers (payins). It supports multiple payment methods, card tokenization, recurring payments and 3DS.
Secure
Authentication via merchant key + hash, HTTPS required
Multi-method
Cards, digital wallets, crypto and alternative payment methods
Simple
REST API with clear JSON responses and a ready-to-use payment page
Base URL
Postman Collection
To test the integration faster, download the Postman Collection.
How it works
When a customer wants to buy on your site, your system and Checkout coordinate in a few steps: a payment session is created, the customer fills in their details on the Checkout Page, and your site receives the result via callback.
👉 See the full flow diagram.