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

# Idempotency

> Retry a request safely with an idempotency key and avoid duplicate API work.

Operations marked idempotent use an `Idempotency-Key` header. The Create Post endpoint requires this header when you publish or schedule. The header is optional when you create a draft.

```http theme={null}
Idempotency-Key: 2a4d3947-6ec2-4b88-96cb-c1cfb9a6b37f
```

Create one unique value for each operation. You can use a UUID.

## Retry rules

* Use the same key when you retry the same method, path, and body.
* Use a new key when the method, path, or body changes.
* Do not use one key for different workspaces or endpoints.
* After a timeout, retry the same request or get the resource before you create new work.

OpenPMM returns `409` when an existing key has different input.

<Warning>
  Idempotency prevents duplicate OpenPMM work. It cannot reverse a provider action.
</Warning>