> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chat402.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Error Handling

> Handle API errors properly

## HTTP Status Codes

| Code | Meaning          | Action                   |
| ---- | ---------------- | ------------------------ |
| 200  | Success          | Process response         |
| 400  | Bad Request      | Check request parameters |
| 401  | Unauthorized     | Verify API key           |
| 402  | Payment Required | Top up wallet balance    |
| 404  | Not Found        | Check endpoint URL       |
| 500  | Internal Error   | Retry or contact support |

## Error Response Format

```json theme={null}
{
  "error": "Insufficient balance: has $0.50, needs $1.00",
  "code": "INSUFFICIENT_BALANCE",
  "details": {
    "currentBalance": 0.50,
    "requiredBalance": 1.00,
    "deficit": 0.50
  }
}
```

## Common Error Codes

* `INVALID_API_KEY` - API key is missing or invalid
* `INVALID_MODEL` - Unsupported model specified
* `INSUFFICIENT_BALANCE` - Not enough USDC in wallet
* `PAYMENT_VERIFICATION_FAILED` - Payment signature invalid
* `RATE_LIMIT_EXCEEDED` - Too many requests
* `INTERNAL_ERROR` - Server error

## Example Error Handling

```javascript theme={null}
try {
  const result = await chat(prompt);
  console.log(result.text);
} catch (error) {
  if (error.response?.status === 402) {
    console.error('Please top up your wallet');
  } else {
    console.error('Error:', error.message);
  }
}
```