# Getting Started

This section will guide you through the initial steps to set up and begin using the 21X SDK.

***

## Prerequisites

Before you start, ensure you have the following:

1. **Python Version**: Ensure Python 3.97 or higher is installed on your system.
2. **Access Credentials**: Obtain an API key for the REST API and ensure your wallet is registered and whitelisted in the 21X platform.
3. **Polygon Wallet**: Use a funded wallet on the Polygon network to cover gas fees for smart contract interactions.
4. **Polygon RPC Provider**: Access a Polygon-compatible RPC endpoint (e.g., Infura, Alchemy, or a self-hosted node) for blockchain communication.

## Installation

Install the SDK using pip:

```bash
pip install 21x-sdk
```

## Basic Setup

### 1. Initialize the REST API Client

The REST API client is used to interact with platform features like fetching open orders and price information.

```python
from x21_sdk import Client, AuthenticatedClient

# Initialize either a client for the public endpoints
client = Client(base_url="<insert the 21X API url here>")

# Or a Client to use the authenticated endpoints
client = AuthenticatedClient(
    base_url="<insert the 21X API url here>",
    client_id="<insert the client id here>",
    client_secret="<insert the client secret here>",
    token_endpoint="<insert the oidc token endpoint here>",
)
```

Alternatively, you can make use the following environment variables, to auto configure the clients.

```bash
export 21X_BASE_URL=<>
export 21X_AUTH_CLIENT_ID=<>
export 21X_AUTH_CLIENT_SECRET=<>
export 21X_AUTH_CLIENT_TOKEN_ENDPOINT=<>
```

```python
from x21_sdk import Client, AuthenticatedClient

# Initialize either a client for the public endpoints
client = Client()

# Or a Client to use the authenticated endpoints
client = AuthenticatedClient()
```

### 2. Example: Fetch Available Trading Pairs

Use the REST API client to list all trading pairs:

```python
from x21_sdk.client.api.public_market_data import get_trading_pairs

trading_pairs = get_trading_pairs.sync(client=client)
for pair in trading_pairs.items:
    print("orderbook_addr: " + pair.smart_contract_order_book)
    print("base: " + pair.base_token_data.symbol)
    print("quote: " + pair.quote_token_symbol)
```

### 3. Initialize the OrderBook Class

The `OrderBook` class is your entry point for interacting with the EVM-based smart contract.

```python
from x21_sdk import OrderBook

# Initialize the OrderBook class with your private key and RPC URL
order_book = OrderBook(
  private_key="your_private_key",
  orderbook_addr="0xOrderBookAddress",
  rpc_url="https://polygon-mainnet.g.alchemy.com/v2/YOUR_API_KEY",
)
```

### 4. Example: Check Token Balances

Here’s how you can check the token balances for a trading pair:

```python
balances = order_book.get_balance()

print(f"Base Token Balance: {balances.base}")
print(f"Quote Token Balance: {balances.quote}")
```