# What does the VARTA error `unauthenticated` mean?

The request carried no usable credential.


**HTTP status:** `401`  ·  **Type:** `authentication_error`

## What it means

The request carried no usable credential.

## What causes it

Raised when the authentication dependency can't establish who is calling (`backend/app/security/deps.py`) — no `Authorization` header, or a header that produces no principal.

On an instance running in enforce mode, this is usually caught earlier: the auth middleware rejects a missing or invalid `Authorization` header before the `/v1` error handlers ever run, and that rejection is a plain `{"detail": "authentication required"}` response with status 401 and none of this page's envelope fields — no `type`, `code`, `request_id` or `doc_url` (`backend/app/security/middleware.py:48-50`). The enveloped form described on this page is what the `/v1` handlers themselves produce; a developer who instead sees the bare `{"detail": ...}` form should still treat it as this error.

## What to do

Send a valid `Authorization: Bearer <api_key>` header on every `/v1` request.