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

# Install the SDK

> Install @sayless/sdk and authenticate with an API key or OAuth token.

## Requirements

* Node.js **18+** (uses global `fetch`)
* A personal API key (`sl_api_…`) or OAuth access token (`sl_oat_…`) from [Settings → API](/admin/api-and-webhooks)

## Install

```bash theme={"system"}
npm install @sayless/sdk
# or
yarn add @sayless/sdk
# or
pnpm add @sayless/sdk
```

The package lives in the Sayless monorepo at `app-mlp/packages/sdk` and is generated from the gateway OpenAPI contract.

## Authenticate

```ts theme={"system"}
import { SaylessClient } from '@sayless/sdk';

const sayless = new SaylessClient({
  apiKey: process.env.SAYLESS_API_KEY,
  // or: accessToken: process.env.SAYLESS_ACCESS_TOKEN,
  apiUrl: process.env.SAYLESS_API_URL, // optional; defaults to https://api.sayless.ai
});
```

Never commit keys. Prefer environment variables in CI and local `.env` files that stay gitignored.

## Next

* [Client options](/developers/sdk/client)
* [Examples](/developers/sdk/examples)
* [API overview](/developers/api/overview)