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

# Foundational API Quickstart

> Learn how to integrate GoldRush APIs into your application in minutes. Get started with our TypeScript SDK to access multichain blockchain data.

## Introduction

This quickstart guide walks through using the [GoldRush TypeScript SDK](https://goldrush.dev/docs/goldrush-sdks.md) to quickly build with multichain data leveraging the powerful GoldRush APIs.

## Prerequisites

Using any of the GoldRush developer tools requires an API key. Start on the free tier and [compare plans and pricing](https://goldrush.dev/pricing/) before you scale.

> [card] [Vibe Coders](https://goldrush.dev/platform/auth/register/?plan=vibe)
>
> \$10/mo - Built for solo builders and AI-native workflows.

> [card] [Teams](https://goldrush.dev/platform/auth/register/?plan=professional)
>
> \$250/mo - Production-grade with 50 RPS and priority support.

## Supported Chains

GoldRush can be used with any of the supported chains. See the full list, including chain categorization, at [Supported Chains](https://goldrush.dev/chains/).

> [!NOTE]
>
> Some data enrichments such as internal transactions and historical balance fetches are only available for Foundational Chains.

## Using the GoldRush TypeScript SDK

The GoldRush TypeScript SDK is the fastest way to integrate the GoldRush APIs for working with blockchain data. The SDK works with all supported chains.

> [!NOTE]
>
> This SDK requires NodeJS v18 or above.

### Step 1. Install the SDK

```bash npm theme={null}
npm install @covalenthq/client-sdk
```

```bash yarn theme={null}
yarn add @covalenthq/client-sdk
```

See the package on [npmjs](https://www.npmjs.com/package/@covalenthq/client-sdk) for more details.

### Step 2. Import the Client

The `GoldRushClient` class provides typesafe, easy-to-use helper functions and classes to use the GoldRush APIs.

```typescript theme={null}
import { GoldRushClient } from "@covalenthq/client-sdk";
```

### Step 3. Initialize the Client

```typescript theme={null}
import { GoldRushClient } from "@covalenthq/client-sdk";

const ApiServices = async () => {
    const client = new GoldRushClient("<GOLDRUSH_API_KEY>"); 
};
```

### Step 4. Invoke the Service

In this quickstart, we use the `BalanceService` and `getTokenBalancesForWalletAddress()` function to fetch all token balances held by an address. This function takes a chain name and wallet address as required arguments.

> [!NOTE]
>
> ENS resolution is supported for `eth-mainnet`.

```typescript theme={null}
import { GoldRushClient } from "@covalenthq/client-sdk";

const ApiServices = async () => {
    // Replace with your GoldRush API key
    const client = new GoldRushClient("<GOLDRUSH_API_KEY>"); 
    const response = await client.BalanceService.getTokenBalancesForWalletAddress("eth-mainnet", "demo.eth"); 
    
    if (!response.error) {
        console.log(response.data);
    } else {
        console.log(response.error_message);
    }
};

ApiServices();
```

Example response:

```json theme={null}
{
    "address": "0xfc43f5f9dd45258b3aff31bdbe6561d97e8b71de",
    "chain_id": 1,
    "chain_name": "eth-mainnet",
    "quote_currency": "USD",
    "updated_at": "2024-11-05T22:18:41.522Z",
    "items": [
        {
            "contract_decimals": 6,
            "contract_name": "Tether USD",
            "contract_ticker_symbol": "USDT",
            "contract_address": "0xdac17f958d2ee523a2206206994597c13d831ec7",
            "contract_display_name": "Tether USD",
            "supports_erc": [],
            "logo_url": "https://logos.covalenthq.com/tokens/1/0xdac17f958d2ee523a2206206994597c13d831ec7.png",
            "last_transferred_at": "2024-08-28T12:43:35.000Z",
            "native_token": false,
            "type": "stablecoin",
            "is_spam": false,
            "balance": "3007173042",
            "balance_24h": "3007173042",
            "quote_rate": 1,
            "quote_rate_24h": 0.9992,
            "quote": 3007.173,
            "quote_24h": 3004.7673,
            "pretty_quote": "$3,007.17",
            "pretty_quote_24h": "$3,004.77",
            "logo_urls": {},
            "protocol_metadata": null,
            "nft_data": null
        }
    ]
}
```


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