# `idempotency_key_reused`

A Multiplayer API error, sent with HTTP 409. Status: the Multiplayer API is in private alpha; this code is part of its published contract.

## When

The same Idempotency-Key came with a different body.

## What to do

Use a new Idempotency-Key for a different request; reuse a key only to retry the exact same request.

## 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": "idempotency_key_reused",
  "detail": "A sentence that is safe to show.",
  "next": "Use a new Idempotency-Key for a different request; reuse a key only to retry the exact same request.",
  "docsUrl": "https://lobbylab.gg/docs/errors/idempotency_key_reused"
}
```

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