# `IDEMPOTENCY_KEY_REQUIRED` Idempotency-Key required

Source: https://checkslip.com/en/problems/idempotency-key-required

- **HTTP status**: `400`
- **Credit**: No credit taken

## Meaning

This action creates or changes data or spends credit, so it needs an `Idempotency-Key` header to be safely retried.

## Fix

Send an `Idempotency-Key` header with a new value per request (e.g. a UUID), and reuse it when retrying.

## Example response

```
{
  "type": "https://checkslip.com/problems/idempotency-key-required",
  "title": "Idempotency-Key required",
  "status": 400,
  "code": "IDEMPOTENCY_KEY_REQUIRED",
  "instance": "01a18600-0000-7000-8000-000000000000"
}
```