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

# IDEMPOTENCY_KEY_REUSED

> This `Idempotency-Key` was already used for a different request.

`409 Conflict` · type `conflict`

**When it happens**

Within the last 24 hours, the same key was sent with a different request: another path, another body, or another acting broker. Bodies are compared byte for byte, so re-serializing the same data can count as different (keys reordered, spacing changed).

**What to do**

Use a new key for a new request. To retry, resend the exact bytes you sent the first time. See [idempotency](/guides/idempotency).

## Example

```json 409 Conflict theme={null}
{
  "error": {
    "type": "conflict",
    "code": "IDEMPOTENCY_KEY_REUSED",
    "message": "This Idempotency-Key was already used with a different request or credential. Use a new key for a new request.",
    "param": "Idempotency-Key",
    "doc_url": "https://docs.bridgelinepf.com/errors#IDEMPOTENCY_KEY_REUSED",
    "request_id": "req_8fJ2kQ9xLm4TzW7nB3cY5pDv"
  }
}
```

See all [error codes](/errors), or how to [handle errors](/guides/errors).


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