> ## 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.

# Harmony Onchain Data API

> Get token balances and transactions for Harmony. Testnet supported.

## Overview

<Tip>
  Explore Harmony, the open blockchain with 2-second finality, low fees, and secure cross-chain bridges for Ethereum apps. Dive into historical data now!
</Tip>

GoldRush offers the most comprehensive Harmony Data API suite for developers, analysts, and enterprises. Whether you're
building a DeFi dashboard, a wallet, a trading bot, an AI agent or a compliance platform,
our Harmony Data APIs provide fast, accurate, and developer-friendly access to the essential onchain data you need.

### Supported APIs

<Columns cols={2} />

## Mainnet

| Property             | Value                                       |
| -------------------- | ------------------------------------------- |
| **Chain Name**       | `harmony-mainnet`                           |
| **Chain ID**         | `1666600000`                                |
| **Network Type**     | Archived Chain                              |
| **Support Level**    | archived                                    |
| **Block Explorer**   | [Explorer](https://explorer.harmony.one/)   |
| **Official Website** | [Harmony Website](https://www.harmony.one/) |
| **Native Gas Token** | ONE                                         |

## Testnet

| Property             | Value                                               |
| -------------------- | --------------------------------------------------- |
| **Chain Name**       | `harmony-testnet`                                   |
| **Chain ID**         | `1666700000`                                        |
| **Purpose**          | Development and testing network                     |
| **Support Level**    | archived                                            |
| **Block Explorer**   | [Explorer](https://explorer.testnet.harmony.one/)   |
| **Official Website** | [Harmony Testnet Website](https://www.harmony.one/) |
| **Native Gas Token** | ONE                                                 |

## API Usage

To use this blockchain network in GoldRush API calls, use:

#### Chain Name

* `harmony-mainnet` (mainnet)
* `harmony-testnet` (testnet)

#### Example Streaming Subscription

<CodeGroup>
  ```graphql GraphQL Subscription theme={null}
  subscription {
    walletTxs(
      chain_name: HARMONY_MAINNET,
      wallet_addresses: ["0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"]
    ) {
      block_signed_at
      block_height
      tx_hash
      tx_offset
      successful
      decoded_type
    }
  }
  ```

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

  const client = new GoldRushClient("<GOLDRUSH_API_KEY>");

  client.StreamingService.subscribeToWalletTxs(
    {
      chain_name: StreamingChain.HARMONY_MAINNET,
      wallet_addresses: ["0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"],
    },
    {
      next: (data) => console.log("Received data:", data),
      error: (error) => console.error("Error:", error),
      complete: () => console.log("Stream completed"),
    }
  );
  ```
</CodeGroup>

<Info>
  Connect via WebSocket at `wss://streaming.goldrushdata.com/graphql` with your API key in the connection parameters.
  See the [Streaming API Quickstart](/goldrush-streaming-api/quickstart) for full setup details.
</Info>

## Additional Resources

* [GoldRush API Documentation](https://goldrush.dev/docs/)
* [Supported Chains List](https://goldrush.dev/chains/)
* [API Reference](https://goldrush.dev/docs/api-reference/)