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

# Overview

> Which SDK to use — server libraries for your backend and the frontend SDK for checkout.

Bob offers official SDKs in **two layers**. They solve different problems and are typically used together: a **server** library creates the charge and verifies webhooks on your backend; the **frontend** SDK mounts the checkout and tokenizes the card in the browser.

<Note>
  **Credit card is still coming soon.** Today the SDKs operate with **PIX**; card tokenization in the Checkout SDK arrives when card is launched.
</Note>

## Choose your SDK

| SDK                                    | Layer              | Language / Platform  | When to use                                                                                       |
| -------------------------------------- | ------------------ | -------------------- | ------------------------------------------------------------------------------------------------- |
| [Node.js SDK](/en/pages/sdk/node)      | Server (backend)   | Node.js / TypeScript | Create charges, list transactions, and verify webhooks from your server.                          |
| [PHP SDK](/en/pages/sdk/php)           | Server (backend)   | PHP                  | The same, on PHP stacks.                                                                          |
| [Checkout SDK](/en/pages/sdk/checkout) | Frontend (browser) | JavaScript / React   | Embed Bob's checkout on your site, tokenize the card, and run 3DS without exposing raw card data. |

<Note>
  Secret keys (`sk_live_`, `sk_test_`) only exist on the **server**. Checkout session creation happens on the backend with a server library; the Checkout SDK runs in the browser and only receives the `checkoutToken`.
</Note>

## Typical flow (server + frontend together)

```text theme={"system"}
Your backend  ── Node.js/PHP SDK ──>  creates the checkout session (sk_...)
                                      │
                                      └─ checkoutToken ─> your frontend
Your frontend ── Checkout SDK ──────>  mounts the checkout, tokenizes the card, runs 3DS
```

## No SDK for your language?

All operations are available through the REST API — the SDKs are conveniences on top of it. See the [API Reference](/en/pages/pix/create) and call the endpoints directly from your backend in any language.

<CardGroup cols={3}>
  <Card title="Node.js SDK" icon="node-js" href="/en/pages/sdk/node">
    Official TypeScript/Node.js library for your server.
  </Card>

  <Card title="PHP SDK" icon="php" href="/en/pages/sdk/php">
    Official PHP library for your server.
  </Card>

  <Card title="Checkout SDK" icon="credit-card" href="/en/pages/sdk/checkout">
    Embed Bob's checkout on your site, with card, PIX, and 3DS.
  </Card>
</CardGroup>