# invalid_idempotency_key

**The Idempotency-Key is too long.**

| | |
|---|---|
| HTTP status | `400` |
| `code` | `invalid_idempotency_key` |
| Retry? | No, fix the request first |

## What it means

The `Idempotency-Key` header may be up to 255 characters.

## How to fix it

Use a UUID or another short, unique value. → [Idempotency](https://docs.kalender-sync.de/en/api/idempotency/)

## Example

```json
{
  "type": "https://docs.kalender-sync.de/en/api/errors/invalid_idempotency_key",
  "title": "The request is invalid",
  "status": 400,
  "code": "invalid_idempotency_key",
  "detail": "Idempotency-Key may be up to 255 characters.",
  "request_id": "req_…"
}
```

→ [All error codes](https://docs.kalender-sync.de/en/api/errors/)