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

# Authentication

> Shared authentication reference, referenced from every endpoint page instead of repeated.

[← Back to API Integration](/integration/api-integration)

Every endpoint in this reference requires authentication. Send your key in the `X-API-Key` header — the same three headers apply everywhere, so they're listed once here rather than repeated on each endpoint page.

| Header         | Value              | Notes                                                                                           |
| -------------- | ------------------ | ----------------------------------------------------------------------------------------------- |
| `X-API-Key`    | `<your key>`       | Required. Scoped to one partner ID. Keep it server-side — never ship it in browser or app code. |
| `Accept`       | `application/json` | Recommended on every request.                                                                   |
| `Content-Type` | `application/json` | Required on POST requests that send a body.                                                     |

<Warning>
  A missing or wrong key returns `401` with a short error string — not a JSON validation object. Handle both shapes; see [Errors](/integration/api-integration/errors).
</Warning>