> For the complete documentation index, see [llms.txt](https://docs.baas.sh/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.baas.sh/baas-sdk/quickstart.md).

# Quickstart

This guide takes you from an empty project to a signed-in user. It should take just a few minutes.

{% hint style="info" %}
The SDK runs in the **browser** and needs **HTTPS** (`localhost` is exempt). See the [Introduction](/baas-sdk/sdk.md) for the full prerequisites.
{% endhint %}

{% stepper %}
{% step %}

### Install the SDK

{% tabs %}
{% tab title="npm" %}

```bash
npm install @baas/sdk
```

{% endtab %}

{% tab title="pnpm" %}

```bash
pnpm add @baas/sdk
```

{% endtab %}

{% tab title="yarn" %}

```bash
yarn add @baas/sdk
```

{% endtab %}
{% endtabs %}
{% endstep %}

{% step %}

### Get your credentials

You need three values to connect the SDK to your project:

* `projectId` and `apiUrl` — from your **BaaS Dashboard**
* `publishableKey` (starts with `sb_publishable_`) and `apiUrl` — from your project's **BaaS Console**

{% hint style="info" %}
Store these in environment variables rather than hard-coding them. The publishable key is meant to be public (it ships in your client bundle), but using env vars keeps configuration clean across environments.
{% endhint %}
{% endstep %}

{% step %}

### Initialize the client

Create the client **once**, at the root of your app. It's **synchronous**, so `getSession()` works right away. The SDK fetches your project's networks lazily, on the first sign-in.

{% code title="baas.ts" %}

```ts
import { createBaasClient } from '@baas/sdk';

export const baas = createBaasClient({
  projectId:      'my-baas-project',
  publishableKey: 'sb_publishable_xxx',
  apiUrl:         'https://my-project-api.baas.sh',
});
```

{% endcode %}
{% endstep %}

{% step %}

### Create the user's account

For a brand-new user, create a passkey and sign in:

```ts
const session = await baas.auth.signUp();
//  → { address: '0x…', accessToken: 'eyJ…', expiresAt: 1735689600 }
```

A **returning** user signs in with their existing passkey instead:

```ts
const session = await baas.auth.signIn();
```

Both default to passkeys. See [Authentication](/baas-sdk/authentication.md) for wallet sign-in and the difference between sign up and sign in.
{% endstep %}

{% step %}

### React to auth state

Keep your UI in sync with the session. The callback fires immediately with the current state, then on every change.

```ts
const unsubscribe = baas.auth.onAuthStateChange((session) => {
  if (session) console.log('Signed in as', session.address);
  else         console.log('Signed out');
});
```

{% endstep %}

{% step %}

### Sign out

```ts
await baas.auth.signOut();
```

{% endstep %}
{% endstepper %}

{% hint style="success" %}
**`signIn()` and `signUp()` are zero-config shortcuts** (passkey by default), perfect for getting started in one line. When you need wallet sign-in or finer control, reach for the explicit methods covered in [Authentication](/baas-sdk/authentication.md).
{% endhint %}

<details>

<summary>Going to production</summary>

Two things to check before you ship, both configured outside the SDK:

* **CORS / origin** — sign-in and token refresh rely on an `HttpOnly` cookie, so the SDK sends requests with credentials. In production, **your app's origin must be allowed by your BaaS API** (credentialed CORS, no wildcard origin), otherwise token refresh fails silently. This is configured per project on the API side.
* **HTTPS** — required on any domain other than `localhost` (passkeys and WebAuthn need a secure origin).

</details>

## Next steps

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>Authentication</strong></td><td>Passkeys, wallets, and the sign up vs sign in model.</td><td><a href="/pages/f0kFN583tRSVnXa7wuan">/pages/f0kFN583tRSVnXa7wuan</a></td></tr><tr><td><strong>Integration guides</strong></td><td>Framework guides, supported bundlers, and TypeScript setup.</td><td><a href="/pages/1q4AjEG7o1BZ5Z6hEuwV">/pages/1q4AjEG7o1BZ5Z6hEuwV</a></td></tr><tr><td><strong>Blockchain interactions</strong></td><td>Call your smart contracts, send transactions, and switch networks.</td><td><a href="/pages/Djvoam2RWqSjubUCII8o">/pages/Djvoam2RWqSjubUCII8o</a></td></tr></tbody></table>


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