> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ionicfi.com/llms.txt
> Use this file to discover all available pages before exploring further.

# SDKs

> Official libraries for the server, the browser, and React.

Ionic ships three packages. Which one you install depends on where the code
runs: your server can hold a secret key; the browser must never see one.

| Package                         | Runs                | Holds                    | Use it for                                                           |
| ------------------------------- | ------------------- | ------------------------ | -------------------------------------------------------------------- |
| [`@ionicfi/sdk`](/sdks/server)  | Your server         | Secret key (`sk_…`)      | Every API call: sessions, payments, customers, webhooks verification |
| [`@ionicfi/js`](/sdks/browser)  | The browser         | Session credentials only | Mounting embedded checkout on your page                              |
| [`@ionicfi/react`](/sdks/react) | The browser (React) | Nothing extra            | `<CheckoutEmbed>`: embedded checkout as a component                  |

The server SDK's methods and types match the
[API reference](/api-reference/overview) exactly. The browser packages load
their runtime from Ionic's CDN at mount time, so security updates reach your
integration without a redeploy.

## Typical setups

* **Backend + hosted checkout**: `@ionicfi/sdk` only. Create sessions
  server-side, redirect the buyer, fulfill from webhooks.
* **Backend + embedded checkout (React app)**: `@ionicfi/sdk` on the server,
  `@ionicfi/react` in the frontend.
* **Backend + embedded checkout (any other frontend)**: `@ionicfi/sdk` on the
  server, `@ionicfi/js` (or a plain script tag) in the frontend.
* **Not on Node?** Every SDK call has a raw HTTP equivalent in the
  [API reference](/api-reference/overview); the guides show both side by side.