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

# Idempotency

> Safely retry order requests without creating duplicates.

Network calls fail, time out, and get retried. To make ordering safe, Kalixo uses your
**`externalOrderCode`** as an idempotency key.

## How it works

* `externalOrderCode` must be **unique per order** within your account.
* If you `POST /orders` again with an `externalOrderCode` that already exists, Kalixo does
  **not** create a second order - it returns the **existing** order instead.
* This means you can safely retry a request whose response you never received.

<Note>
  Generate a stable `externalOrderCode` **before** you send the request (for example, your
  own order reference), so a retry uses the exact same code.
</Note>

## Example

The first call creates the order; an identical retry returns the same `orderId`.

```bash theme={"dark"}
curl -X POST "https://api.kalixo.io/v2/orders" \
  -H "x-api-key: $KALIXO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "externalOrderCode": "O-12345",
    "currency": "GBP",
    "price": 10000,
    "orderProducts": [{ "productCode": "10020000213575", "price": 10000, "quantity": 1 }]
  }'
```

<Warning>
  Reusing an `externalOrderCode` with a **different** payload does not modify the original
  order. Always use a new code for a genuinely new order.
</Warning>