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

# Errors

> Error response format and all error types

All errors use a consistent JSON shape:

```json theme={null}
{
  "error": {
    "type": "invalid_request",
    "code": "missing_required_field",
    "message": "title is required",
    "param": "title",
    "requestId": "req_550e8400-e29b-41d4-a716-446655440000"
  }
}
```

| Field       | Description                                                       |
| ----------- | ----------------------------------------------------------------- |
| `type`      | High-level error category (see below)                             |
| `code`      | Machine-readable error code within the type                       |
| `message`   | Human-readable description                                        |
| `param`     | The field that caused the error, if applicable                    |
| `requestId` | Unique ID for this request — include this when contacting support |

## Error types

| Type              | HTTP status | When it happens                             |
| ----------------- | ----------- | ------------------------------------------- |
| `invalid_request` | 400         | Missing field, bad format, or invalid value |
| `authentication`  | 401         | Missing, invalid, or revoked API key        |
| `permission`      | 403         | API key lacks the required scope            |
| `not_found`       | 404         | The requested resource doesn't exist        |
| `conflict`        | 409         | Idempotency key reused with different body  |
| `rate_limited`    | 429         | Too many requests — back off and retry      |
| `server`          | 500         | Unexpected server error                     |

## Handling errors

Check the HTTP status code first, then branch on `error.type` for programmatic handling.

```ts theme={null}
try {
  const session = await client.checkoutSessions.create({ ... });
} catch (e) {
  if (e instanceof CheckoutApiError) {
    switch (e.type) {
      case "authentication":
        // Prompt user to reconfigure their API key
        break;
      case "rate_limited":
        // Implement exponential backoff
        await sleep(e.retryAfter ?? 1000);
        break;
      case "invalid_request":
        // Surface e.param and e.message to the user
        break;
    }
  }
}
```