> ## Documentation Index
> Fetch the complete documentation index at: https://terminal49-mintlify-changelog-april-1775488342.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Error Handling

> Catch and handle errors from the Terminal49 SDK

The SDK throws typed errors you can catch and handle based on the error type.

## Error types

| Error                    | Cause                                      |
| ------------------------ | ------------------------------------------ |
| `AuthenticationError`    | Invalid or missing API token               |
| `AuthorizationError`     | Valid token but insufficient permissions   |
| `NotFoundError`          | Resource doesn't exist or isn't accessible |
| `ValidationError`        | Invalid request parameters                 |
| `RateLimitError`         | Too many requests                          |
| `FeatureNotEnabledError` | Feature requires a plan upgrade            |
| `UpstreamError`          | Carrier or terminal API is unavailable     |
| `Terminal49Error`        | Generic error fallback                     |

## Basic error handling

```typescript theme={null}
import {
  Terminal49Client,
  AuthenticationError,
  RateLimitError,
  NotFoundError,
} from '@terminal49/sdk';

const client = new Terminal49Client({
  apiToken: process.env.T49_API_TOKEN!,
});

try {
  await client.containers.get('container-uuid');
} catch (error) {
  if (error instanceof AuthenticationError) {
    console.error('Invalid API token');
  } else if (error instanceof NotFoundError) {
    console.error('Container not found');
  } else if (error instanceof RateLimitError) {
    console.error('Rate limited, retrying in 60s');
    await new Promise((resolve) => setTimeout(resolve, 60000));
  } else {
    throw error;
  }
}
```

## Automatic retries

The SDK automatically retries `429` and `5xx` responses with exponential backoff up to `maxRetries` (default: 2).

```typescript theme={null}
const client = new Terminal49Client({
  apiToken: process.env.T49_API_TOKEN!,
  maxRetries: 3,
});
```

## Error properties

All SDK errors include:

| Property  | Type    | Description                      |
| --------- | ------- | -------------------------------- |
| `message` | string  | Human-readable error description |
| `status`  | number  | HTTP status code                 |
| `details` | unknown | Raw error payload from the API   |