# `unsupported_media_type`

A Multiplayer API error, sent with HTTP 415. Status: the Multiplayer API is in private alpha; this code is part of its published contract.

## When

The body is not `application/json`.

## What to do

Send JSON with the header `Content-Type: application/json`.

## The answer

Every error is a JSON body with a stable `error` code. Clients act on the codes they know and treat any other code as a failure of its HTTP status, and keep fields they do not know.

```json
{
  "error": "unsupported_media_type",
  "detail": "A sentence that is safe to show.",
  "next": "Send JSON with the header `Content-Type: application/json`.",
  "docsUrl": "https://lobbylab.gg/docs/errors/unsupported_media_type"
}
```

See also: [every error code](/docs/errors), [the API reference](/docs/api) and [the docs](/docs).