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

# Installation

> Install the Compose SDK and its peer dependencies.

## Install

```bash theme={null}
npm install @compose-market/sdk
```

## Peer dependencies

The SDK depends on `viem` for EVM wallet operations (x402 payment signing). It's installed automatically as a dependency.

For raw x402 payments (without a Compose Key), you also need `@x402/core` and `@x402/evm`:

```bash theme={null}
npm install @x402/core @x402/evm
```

These are already included as dependencies of `@compose-market/sdk`, so you only need to install them separately if you're using x402 outside the SDK.

## Requirements

* **Node.js 20.6+** (uses native `fetch`, `ReadableStream`, `TextDecoder`, `WebCrypto`)
* **TypeScript 5+** (if using TypeScript — the SDK ships with type definitions)

## Initialize

```typescript theme={null}
import ComposeSDK from "@compose-market/sdk";

const sdk = new ComposeSDK({
  userAddress: "0xYourWalletAddress",
  chainId: 43113, // Avalanche Fuji testnet
});
```

### Configuration options

| Option        | Type                   | Default                           | Description                                                                                 |
| ------------- | ---------------------- | --------------------------------- | ------------------------------------------------------------------------------------------- |
| `userAddress` | `string`               | —                                 | Your EVM wallet address. Required for all billable calls.                                   |
| `chainId`     | `number`               | —                                 | Chain ID for x402 settlement. Call `sdk.x402.facilitator.chains()` to see supported chains. |
| `baseUrl`     | `string`               | `https://api.compose.market`      | API base URL.                                                                               |
| `channelsUrl` | `string`               | `https://services.compose.market` | Channels service base URL.                                                                  |
| `key`         | `string`               | —                                 | A previously issued Compose Key JWT. Stored and reused automatically.                       |
| `storage`     | `Storage`              | in-memory                         | Token storage adapter. Browser `localStorage` is auto-detected.                             |
| `timeoutMs`   | `number`               | `60000`                           | Per-request timeout in milliseconds.                                                        |
| `retry`       | `Partial<RetryPolicy>` | `{ maxRetries: 2 }`               | Retry policy for transient errors (5xx, 429, network).                                      |
| `userAgent`   | `string`               | `@compose-market/sdk/<version>`   | User-Agent suffix for analytics.                                                            |

## Authentication

There are two ways to authenticate:

1. **Compose Key** (recommended): A bearer token issued by `sdk.keys.create()`. No wallet signing needed — just pass `userAddress` and `chainId`. The SDK handles token storage and refresh automatically.

2. **Raw x402**: Sign each request with an EVM wallet. No Compose Key needed, but every call requires a payment signature. Use this for agent-to-agent calls where no human is in the loop.

See [Payments Overview](/sdk/payments/overview) for the full comparison.