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

# idempotency-key-reused

> 409 — same Idempotency-Key, different content

<Info>
  **Quick Summary:** This `Idempotency-Key` was already used for a request with **different** method, path or body. Keys identify one exact request; use a fresh key for new content.
</Info>

## What happened

Within a key 24-hour lifetime, resending the same key with the same content replays the stored response (with `Idempotency-Replayed: true`). Sending the same key with different content is always an error — otherwise a retry could silently perform the wrong operation.

## Likely causes

* Reusing one constant key for many different requests.
* Building the key from something that does not change with the payload.

## What to do

Generate a unique key (a UUID is ideal) per logical operation, reuse it **only** for retries of that exact request, and never share keys across different payloads.