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

# Errors

> HTTP status codes the API returns and how to respond to each.

Errors follow the OpenAI-compatible shape: an HTTP status plus a JSON body with an
`error` object.

```json theme={null}
{
  "error": {
    "message": "key not allowed to access model. Tried to access primalabs-ai/does-not-exist",
    "type": "key_model_access_denied",
    "param": "model",
    "code": "403"
  }
}
```

## Status codes

| Status | Meaning                                                                   | What to do                                                                         |
| ------ | ------------------------------------------------------------------------- | ---------------------------------------------------------------------------------- |
| `400`  | Bad request — malformed JSON, missing or invalid parameters.              | Fix the request; do not retry unchanged.                                           |
| `401`  | Missing or invalid API key.                                               | Check the `Authorization` header and the key.                                      |
| `403`  | The key cannot access this model — including model IDs that do not exist. | Check the `model` against [`GET /models`](/inference/models).                      |
| `404`  | Unknown route.                                                            | Check the URL path against the [endpoint list](/inference/introduction#endpoints). |
| `429`  | Rate limited — one of the three [limits](/inference/rate-limits) tripped. | Back off and retry with jitter; honor `Retry-After`.                               |
| `500`  | Unexpected server error.                                                  | Retry with backoff; if it persists, contact support.                               |
| `502`  | Upstream error reaching the model.                                        | Retry with backoff.                                                                |
| `503`  | No healthy capacity for the model right now.                              | Retry shortly; check the [status page](https://status.primalabs.ai).               |

<Note>
  A typo in the model ID returns **`403`**, not `404` — the API answers in terms of what
  your key may access, so an unknown model and a model you are not entitled to look the same.
</Note>

## Retry guidance

* **Retryable:** `429`, `500`, `502`, `503` — use exponential backoff with jitter.
* **Not retryable as-is:** `400`, `401`, `403`, `404` — the request or credentials must
  change first; retrying unchanged will fail the same way.

<Info>
  The `message` field is meant for logs and debugging, not for pattern-matching in code.
  Branch on the **HTTP status**, which is stable, rather than on the message text.
</Info>