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RadiumOne gives you three building blocks: a hosted payment page, an embeddable card-fields SDK, and a REST API that both of them (and you) call to move money.

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Components

  • RadiumOne Checkout — a RadiumOne-hosted payment page. Redirect the shopper to it, or embed it in an iframe on your own page. The shopper enters their card details there, not on your site.
  • RadiumOne Elements — a JavaScript SDK you load in your own page. It renders secure card fields and tokenizes the card in the browser, so your server never touches raw card data.
  • RadiumOne Payments API — the REST API behind both integrations. Your server calls it to create sessions, charge, capture, void, refund, and check a transaction’s status. It’s also where webhook events come from.
Every integration in Choose your integration combines one of the first two with the Payments API.

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Key objects

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Environments

RadiumOne has separate sandbox and production environments, each with its own hosts and keys. Sandbox and production use separate credentials, hosts and webhook endpoints — see Sandbox and API keys.

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How it works

  1. The shopper starts a purchase on your website.
  2. Your server creates a checkout session (hosted checkout) or a payment session (Elements) by calling the RadiumOne Payments API with your secret key.
  3. The shopper enters their card on RadiumOne Checkout or in RadiumOne Elements fields on your page — never on your server.
  4. RadiumOne routes the authorization request to the card issuer and returns a result.
  5. Your server confirms the final status with an authenticated request to the Payments API, or by receiving a webhook event.

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Next steps

Choose your integration

Compare hosted checkout and Elements across the 3D Secure options.

Sandbox and API keys

Get sandbox credentials before you write any code.

Quickstart

Accept your first payment in sandbox.

API reference

Full Payments API and Checkout API reference.
Last modified on September 15, 2026