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Therius is a payment API that lets you accept cards, digital wallets, and over 40 alternative payment methods — Pix, ACH, iDEAL, Klarna, Apple Pay, and more — through a single endpoint. This documentation covers everything from your first sandbox call to managing subscriptions, handling 3D Secure challenges, and integrating the JS SDK for browser-safe card collection.

Quick Start

Fire your first payment in under 5 minutes with nothing but a sandbox key and a terminal.

Authentication

Learn how API keys work, which key to use where, and how to pass credentials correctly.

API Reference

Complete reference for every endpoint — purchase, authorize, capture, refund, and more.

JS SDK

Collect card details safely in the browser using hosted fields or the drop-in Checkout Widget.

Connections

Browse the full catalog of payment methods — with working code examples for each.

Subscriptions

Build recurring billing with plans, trials, dunning, pause/resume, and plan changes.

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How Therius Works

Every payment — card, wallet, or alternative method — flows through the same /payment/purchase endpoint. You choose the payment method by passing a paymentMethod field (or omitting it for cards). The response always has the same shape, so your backend doesn’t need separate code paths per method.
1

Get a sandbox key

Your Therius account includes a sandbox key (prv_sandbox_...) out of the box. It routes to a test-provider stub — nothing touches a real card network.
2

Make your first API call

Send your key as Authorization: Bearer prv_production_... and fire a POST /payment/purchase. See the Quick Start for a ready-to-run curl command.
3

Integrate the JS SDK (if browser-based)

If you’re accepting cards from a browser, use the JS SDK so raw card numbers never transit your server. The SDK issues a one-time nonce; your server charges the nonce.
4

Go live

Swap prv_sandbox_... for prv_production_... and point at api.therius.io. No other code changes required.

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Key Concepts

Payment Lifecycle

Understand authorize, capture, refund, and cancel flows.

Smart Routing

Route each payment across your acquirers with conditions and cascading failover.

Tokenization

Store cards as reusable tokens for returning shoppers.

3D Secure

Handle 3DS2 challenges without complex branching logic.

Idempotency

Safely retry failed requests without double-charging customers.

Environments

Switch between sandbox and production with a single key prefix.

Alternative Methods

Add Pix, ACH, Klarna, and more with minimal extra code.

Webhooks

Receive signed payment and subscription events on your server.

Testing

Sandbox test cards, decline scenarios, and 3DS test flows.