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

# Perform swaps

> Learn how to swap tokens using the Portal SDK.

Portal provides a built-in swap functionality that allows users to exchange tokens directly from their wallet.

## Token Swaps

The `swap` method allows you to exchange one token for another on supported chains.

### Basic Swap

```dart theme={null}
import 'package:portal_flutter/portal_flutter.dart';

final portal = Portal();

// Perform a swap on Base
final result = await portal.swap(
  swapsApiKey: 'YOUR_SWAPS_API_KEY',
  chainId: 'eip155:8453', // Base mainnet
  sellToken: '0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE', // Native ETH
  buyToken: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913', // USDC on Base
  amount: '1000000000000000', // 0.001 ETH in wei
);

if (result.success) {
  print('Swap successful!');
  print('Transaction hash: ${result.transactionHash}');
} else {
  print('Swap failed');
}
```

<Note>
  You'll need a Swaps API key to use this feature. Contact the Portal team to obtain one.
</Note>

### Swap Parameters

| Parameter     | Description                                              |
| ------------- | -------------------------------------------------------- |
| `swapsApiKey` | Your API key for the swaps service                       |
| `chainId`     | The chain ID in CAIP-2 format                            |
| `sellToken`   | Token address to sell (use `0xEeee...` for native token) |
| `buyToken`    | Token address to buy                                     |
| `amount`      | Amount to sell in the smallest unit (wei for ETH)        |

### Example: Swap USDC to ETH

```dart theme={null}
final result = await portal.swap(
  swapsApiKey: 'YOUR_SWAPS_API_KEY',
  chainId: 'eip155:8453',
  sellToken: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913', // USDC
  buyToken: '0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE', // Native ETH
  amount: '10000000', // 10 USDC (6 decimals)
);
```

## Supported Chains

Token swaps are available on the following chains:

* Ethereum Mainnet (`eip155:1`)
* Base (`eip155:8453`)
* Monad Testnet (`eip155:10143`)
* Arbitrum (`eip155:42161`)
* Optimism (`eip155:10`)
* Polygon (`eip155:137`)

<Warning>
  Always verify token addresses before performing swaps. Incorrect addresses may result in loss of funds.
</Warning>

## Error Handling

```dart theme={null}
try {
  final result = await portal.swap(
    swapsApiKey: 'YOUR_SWAPS_API_KEY',
    chainId: 'eip155:8453',
    sellToken: '0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE',
    buyToken: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913',
    amount: '1000000000000000',
  );

  if (result.success) {
    print('Swap completed: ${result.transactionHash}');
  }
} on PortalException catch (e) {
  print('Swap failed: ${e.message}');
  print('Error code: ${e.code}');
}
```

**Related Documentation**

* [swap function reference](../reference/swap)