# Unsupported media type

_Wispist / Problems_

> HTTP 415 problem returned when a Wispist document mutation does not declare an application/json request body.

Canonical type:

```text
https://learn.peios.org/wispist/problems/unsupported-media-type/
```

Status: `415 Unsupported Media Type`. Browser code: `unsupported_media_type`.

Document create and replacement bodies require:

```http
Content-Type: application/json
```

Media-type parameters such as `charset=utf-8` are accepted, but another base type or a missing header is not. Set the header and send the documented `{"data": {...}}` envelope.

JSON that has the correct media type but invalid content uses [Invalid JSON](/wispist/problems/invalid-json.md) or [Invalid request](/wispist/problems/invalid-request.md).

Related content:

- [Problem Details](/wispist/problems/overview.md)
- [HTTP API reference](/wispist/reference/http-api.md)
- [Invalid JSON](/wispist/problems/invalid-json.md)