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

# Express

> Create an active order and its invoice for an existing account in a single Exsited API call.

Express creates a complete order for an account in one request: the order, its lines and its invoice. This area has 1 endpoint, and every SDK supports it.

## At a glance

| Endpoint | Method | Path | What it does |
| - | - | - | - |
| [Create an order with its invoice](https://exsited.mintlify.site/api-reference/express/create-an-order-with-its-invoice.md) | POST | `/express` | Creates an active order for an existing account in one call and returns it under `express`. |

## Before you call

Register your API credentials once when your app starts, as shown in
[Authentication](https://exsited.mintlify.site/authentication.md). Every SDK sample on these pages then gets its client in one line.
With cURL, send the access token in an `Authorization` header: `Authorization: Bearer $ACCESS_TOKEN`.

## Things to know

* **Send the body under `account`.** Name the account by `id` and nest the order under `account.order`.
* **The order is created active.** The new order's `status` is `active`, and one invoice is raised for it straight away.
* **The response comes back under `express`.** It holds the order as [Retrieve an order](https://exsited.mintlify.site/api-reference/orders/retrieve-an-order.md) returns it, including `lines`, `kpis` and `billing_preferences`.
* **Each line names an item by `item_id`.** `item_price_snapshot.pricing_rule.price` sets the line's price, and `tax_exempt_when_sold` removes tax from the line.


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