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

# Errors and status codes

> Reference common error responses across Forms API.

Forms API uses standard HTTP status codes plus JSON error payloads for most failures.

## Common status codes

* `200 OK`: synchronous read success
* `202 Accepted`: async job accepted
* `400 Bad Request`: request shape is valid but business constraints failed
* `401 Unauthorized`: missing or invalid auth
* `402 Payment Required`: insufficient credits
* `404 Not Found`: job, file, or token not found
* `410 Gone`: download token expired
* `422 Unprocessable Entity`: validation error from request parsing
* `500 Internal Server Error`: unexpected failure
* `503 Service Unavailable`: required storage/service not available

## Error body patterns

You will commonly see one of these shapes:

```json theme={null}
{
  "status": "error",
  "error": "Job not found",
  "job_id": "..."
}
```

```json theme={null}
{
  "detail": "Missing or invalid authentication. Provide X-API-Key header."
}
```

```json theme={null}
{
  "status": "error",
  "error": "insufficient_credits",
  "feature": "parse",
  "required": 12,
  "balance": 3
}
```

## Validation errors

`422` responses use FastAPI validation format and include `detail` with field-level issues (missing form fields, wrong types, etc.).