# Errors

> Failures use one JSON shape. The code is stable. The message is for a person.

Canonical page: https://venuego.co.uk/docs/errors

```json
{
  "error": {
    "code": "invalid_request",
    "message": "sessionId: must be printable ASCII without spaces"
  }
}
```

Responses send `Cache-Control: no-store`. Do not retry a `4xx` as if it might succeed unchanged. A `402` means the account needs a plan or has used its included checks. A `409` `session_closed` on create means that `sessionId` is finished: use a new one. Repeating an open `sessionId` returns `200`, not an error.

| HTTP | Code | When |
| --- | --- | --- |
| 400 | `invalid_json` | The body is not JSON. |
| 400 | `invalid_request` | A field failed validation. `message` names the field. |
| 400 | `invalid_webhook_url` | The webhook URL is not public HTTPS on port 443, or it contains credentials. |
| 400 | `webhook_host_unresolved` | The webhook host did not resolve. |
| 401 | `unauthenticated` | The bearer token is missing, unknown, or revoked. |
| 402 | `trial_exhausted` | The free allowance is used up. |
| 402 | `allowance_exhausted` | This billing period's included checks are used up. |
| 404 | `not_found` | No session exists for that `sessionId` on this account. |
| 409 | `session_closed` | Create was called with a `sessionId` that has already finished. |
| 409 | `not_open` | Cancel was called on a session that is already finished. |
| 413 | `too_large` | The JSON body is over 256 KB. Images and video are not sent to the API. |
| 500 | `internal_error` | Something failed on our side. Retry create with the same `sessionId`. |

A `5xx` or a network timeout on create is safe to retry with the same `sessionId`. If the first call succeeded, the retry returns the existing session.

## What the guest can use

Passports and driving licences issued in the United Kingdom (`GB`), Ireland (`IE`), and the United States (`US`). A passport is the photo page only. A driving licence is the front and the back. The guest also holds that same document beside their face.