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

# Errors

> One error shape, stable codes.

```json theme={null}
{ "error": { "code": "...", "message": "..." } }
```

| HTTP | Code | Meaning |
| - | - | - |
| 400 | `VALIDATION_ERROR` | A malformed handle, address or query parameter. |
| 400 | `BAD_REQUEST` | The request cannot be served as sent. |
| 401 | `UNAUTHORIZED` | Missing or invalid API key. |
| 402 | `QUOTA_EXCEEDED` | Out of credits. Top up at [partner.fomoscan.sh](https://partner.fomoscan.sh). |
| 402 | `REVEAL_LIMIT_REACHED` | The plan's monthly reveal limit is reached. Credits cannot buy past it. |
| 403 | `FORBIDDEN` | The key may not perform this action. |
| 403 | `FORBIDDEN_SCOPE` | Your key is not provisioned for this endpoint. |
| 403 | `FREE_TIER_DISABLED` | The key has no allowance. Buy a plan to continue. |
| 403 | `SAMPLE_SET_ONLY` | A free key asked for a wallet outside the sample set. |
| 403 | `WEBSOCKET_PLAN_REQUIRED` | Your plan has no WebSocket access. Sockets come with Growth and up. |
| 404 | `NOT_FOUND` | No answer for that handle, id or wallet, or no such route. |
| 409 | `CONFLICT` | The request conflicts with one already accepted. |
| 429 | `RATE_LIMITED` | Per-minute limit exceeded. Retry after `retryAfter` seconds. |
| 500 | `INTERNAL_ERROR` | Our fault. Retry. If it persists, contact support with the path and the time. |
| 503 | `OVERLOADED` | We are shedding load. Retry. |
| 503 | `B2B_DISABLED` | The API is switched off on this deployment. |
| 504 | `TIMEOUT` | The answer did not arrive in time. Retry. |

```json theme={null}
{ "error": { "code": "RATE_LIMITED", "message": "rate limit exceeded; retry later", "retryAfter": 12 } }
```

A `404` on a lookup means "no answer today". Cache it briefly and ask again later.
A `404` is charged at the miss price. `401`, `403`, `429` and `5xx` answers are
not charged.


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