# Configuration

## Network & Service Providers

| Service              | Provider   | URL (Mainnet)                   | URL (Testnet)                        |
| -------------------- | ---------- | ------------------------------- | ------------------------------------ |
| **RPC Provider**     | TronGrid   | `https://api.trongrid.io`       | `https://nile.trongrid.io`           |
| **Gas-Free Service** | GasFree.io | `https://open.gasfree.io/tron/` | `https://open-test.gasfree.io/nile/` |

> **Note:** For the latest connection parameters and contract addresses, please refer to the official [GasFree Specification](https://gasfree.io/specification?lang=en-US).

## Wallet Configuration

```javascript
import WalletManagerTronGasfree from '@tetherto/wdk-wallet-tron-gasfree'
import TronWeb from 'tronweb'

// Option 1: Using RPC URL
const config = {
  // Required parameters
  chainId: 728126428, // Blockchain ID
  provider: 'https://api.trongrid.io', // Tron RPC endpoint
  gasFreeProvider: 'https://open.gasfree.io/tron/', // Gas-free service URL
  gasFreeApiKey: 'your-api-key', // Gas-free API key
  gasFreeApiSecret: 'your-api-secret', // Gas-free API secret
  serviceProvider: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH', // Service provider address
  verifyingContract: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH', // Verifying contract address
  
  // Optional parameter
  transferMaxFee: 10000000 // Maximum fee in token base units
}

const wallet = new WalletManagerTronGasfree(seedPhrase, config)

// Option 2: Using TronWeb instance
const tronWeb = new TronWeb({ fullHost: 'https://api.trongrid.io' })
const config2 = {
  chainId: 728126428,
  provider: tronWeb,
  gasFreeProvider: 'https://open.gasfree.io/tron/',
  gasFreeApiKey: 'your-api-key',
  gasFreeApiSecret: 'your-api-secret',
  serviceProvider: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH',
  verifyingContract: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH'
}
```

## Account Configuration

Both `WalletAccountTronGasfree` and `WalletAccountReadOnlyTronGasfree` share similar configuration requirements:

```javascript
import { WalletAccountTronGasfree, WalletAccountReadOnlyTronGasfree } from '@tetherto/wdk-wallet-tron-gasfree'

// Full access account
const account = new WalletAccountTronGasfree(
  seedPhrase,
  "0'/0/0", // BIP-44 derivation path
  {
    chainId: 728126428,
    provider: 'https://api.trongrid.io',
    gasFreeProvider: 'https://open.gasfree.io/tron/',
    gasFreeApiKey: 'your-api-key',
    gasFreeApiSecret: 'your-api-secret',
    serviceProvider: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH',
    verifyingContract: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH',
    transferMaxFee: 10000000 // Optional
  }
)

// Read-only account (transferMaxFee not needed)
const readOnlyAccount = new WalletAccountReadOnlyTronGasfree(
  'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH', // Tron address
  {
    chainId: 728126428,
    provider: 'https://api.trongrid.io',
    gasFreeProvider: 'https://open.gasfree.io/tron/',
    gasFreeApiKey: 'your-api-key',
    gasFreeApiSecret: 'your-api-secret',
    serviceProvider: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH',
    verifyingContract: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH'
  }
)

```

## Configuration Options

### Provider

The `provider` option specifies how to connect to the Tron network.

**Type:** `string | TronWeb`

**Required:** Yes

**Examples:**

```javascript
// Option 1: Using RPC URL
const config = {
  provider: 'https://api.trongrid.io'
}

// Option 2: Using TronWeb instance
const tronWeb = new TronWeb({ fullHost: 'https://api.trongrid.io' })
const config = {
  provider: tronWeb
}

```

### Chain ID

The `chainId` option specifies the blockchain's ID.

**Type:** `number`

**Required:** Yes

**Example:**

```javascript
const config = {
  chainId: 728126428 // Tron Mainnet
}

```

### Gas-Free Provider

The `gasFreeProvider` option specifies the URL of the gas-free service.

**Type:** `string`

**Required:** Yes

**Example:**

```javascript
const config = {
  gasFreeProvider: 'https://open.gasfree.io/tron/'
}

```

### Gas-Free API Key

The `gasFreeApiKey` option is your API key for the gas-free service.

**Type:** `string`

**Required:** Yes

**Example:**

```javascript
const config = {
  gasFreeApiKey: 'your-api-key'
}

```

### Gas-Free API Secret

The `gasFreeApiSecret` option is your API secret for the gas-free service.

**Type:** `string`

**Required:** Yes

**Example:**

```javascript
const config = {
  gasFreeApiSecret: 'your-api-secret'
}

```

### Service Provider

The `serviceProvider` option is the Tron address of the gas-free service provider.

**Type:** `string`

**Required:** Yes

**Example:**

```javascript
const config = {
  serviceProvider: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH'
}

```

### Verifying Contract

The `verifyingContract` option is the Tron address of the contract that verifies gas-free transactions.

**Type:** `string`

**Required:** Yes

**Example:**

```javascript
const config = {
  verifyingContract: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH'
}

```

### Transfer Max Fee

The `transferMaxFee` option sets a maximum limit for transaction fees to prevent unexpectedly high costs.

**Type:** `number | bigint`

**Required:** No (optional)

**Unit:** Token base units

**Example:**

```javascript
const config = {
  transferMaxFee: 10000000 // Maximum fee in token base units
}

// Usage with error handling
try {
  const result = await account.transfer({
    token: 'TR7NHqjeKQxGTCi8q8ZY4pL8otSzgjLj6t',
    recipient: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH',
    amount: 1000000
  }, {
    transferMaxFee: 5000 // Override default max fee
  })
} catch (error) {
  if (error.message.includes('exceeds the transfer max fee')) {
    console.error('Transfer cancelled: Fee too high')
  }
}

```

## Network-Specific Configurations

### Tron Mainnet

```javascript
const mainnetConfig = {
  chainId: 728126428,
  provider: 'https://api.trongrid.io',
  gasFreeProvider: 'https://open.gasfree.io/tron/',
  gasFreeApiKey: 'your-api-key',
  gasFreeApiSecret: 'your-api-secret',
  serviceProvider: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH',
  verifyingContract: 'TFFAMLQZybALab4uxHA9RBE7pxhUAjfF3U' // Official Mainnet Contract
}

```

### Tron Nile Testnet

```javascript
const nileConfig = {
  chainId: 3448148188, // Nile Testnet (Specific ID required for GasFree)
  provider: 'https://nile.trongrid.io',
  gasFreeProvider: 'https://open-test.gasfree.io/nile/',
  gasFreeApiKey: 'your-testnet-api-key',
  gasFreeApiSecret: 'your-testnet-api-secret',
  serviceProvider: 'TLyqzVGLV1srkB7dToTAEqgDSfPtXRJZYH',
  verifyingContract: 'THQGuFzL87ZqhxkgqYEryRAd7gqFqL5rdc' // Official Testnet Contract
}
```

<table data-card-size="large" data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><i class="fa-code">:code:</i></td><td><strong>Node.js Quickstart</strong></td><td>Get started with WDK in a Node.js environment</td><td><a href="../../../start-building/nodejs-bare-quickstart">nodejs-bare-quickstart</a></td></tr><tr><td><i class="fa-mobile-alt">:mobile-alt:</i></td><td><strong>React Native Quickstart</strong></td><td>Build mobile wallets with React Native Expo</td><td><a href="../../../start-building/react-native-quickstart">react-native-quickstart</a></td></tr><tr><td><i class="fa-code">:code:</i></td><td><strong>WDK Tron Gasfree Wallet Usage</strong></td><td>Get started with WDK's Tron Gasfree Wallet Usage</td><td><a href="usage">usage</a></td></tr><tr><td><i class="fa-code">:code:</i></td><td><strong>WDK Tron Gasfree Wallet API</strong></td><td>Get started with WDK's Tron Gasfree Wallet API</td><td><a href="api-reference">api-reference</a></td></tr></tbody></table>

***

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