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

# Idempotency

> Safely retry supported mutations with Idempotency-Key.

Some Leamout mutations are wrapped by the idempotency middleware. Send:

```http theme={null}
Idempotency-Key: <unique key>
```

Keys are scoped to the authenticated organization or principal and must be at most `255` characters.

When a completed request is replayed, Leamout returns the stored response and adds:

```http theme={null}
Idempotency-Replayed: true
```

Reusing a key for a different method, path, or request body returns `409 CONFLICT`. A request already being processed also returns `409` with `Retry-After: 1`.

Idempotent request bodies are capped at `1 MiB`.