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

# Errors & Rate Limits

> HTTP status codes, error envelope, and retry guidance.

## Error envelope

When a request fails, the response shape is:

```json theme={null}
{
  "success": false,
  "request_id": "req_abc123",
  "error": {
    "code": "RATE_LIMIT_EXCEEDED",
    "message": "Daily request quota reached (100 req/day on Free tier)."
  }
}
```

`request_id` is unique per request — include it when reporting issues.

## Status codes

| Code  | Meaning                               | What to do                                                                  |
| ----- | ------------------------------------- | --------------------------------------------------------------------------- |
| `200` | Success                               | —                                                                           |
| `400` | Bad request — invalid params          | Check the parameter table in [API Reference](/api-reference/introduction)   |
| `401` | Unauthorized                          | Verify `X-API-Key` header is set and the key is valid                       |
| `402` | Payment required (Nanopayment)        | Sign EIP-3009 authorization and retry                                       |
| `403` | Forbidden — endpoint not in your plan | Upgrade on [Pricing](/pricing)                                              |
| `404` | Endpoint or symbol not found          | Check spelling, symbol format, or try [the screener](/skills/overview)      |
| `429` | Rate limit exceeded                   | Back off with exponential delay; upgrade plan or use Nanopayment            |
| `500` | Server error                          | Retry after 1–2s; if persistent, [email support](mailto:support@arrays.org) |

## Retry strategy

For idempotent GET requests:

1. **First retry**: wait 1 second
2. **Second retry**: wait 2 seconds
3. **Third retry**: wait 4 seconds
4. **Give up** and surface the error

Always include the `request_id` from the failed response when contacting support.

## Rate limits per plan

| Plan        | Daily requests           | Burst     |
| ----------- | ------------------------ | --------- |
| Free        | 100                      | 10 req/s  |
| Pro         | 10,000                   | 50 req/s  |
| Enterprise  | Custom                   | Custom    |
| Nanopayment | Unlimited (pay-per-call) | 100 req/s |

<Tip>
  The Dashboard shows live usage. Set up a webhook alert at 80% of quota to avoid surprises.
</Tip>