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

# Device Start

The Device Start flow initiates directly at the Nayax terminal, allowing consumers to begin a session by selecting a service or presenting their card. This enables interactive communication with the terminal, such as displaying tariffs or confirming service station availability, before the session officially begins on the machine.

The Device Start flow makes use of the following Spark methods:

* [`StartSession`](/reference/spark/transactions/startsession)
* [`InfoQuery`](/reference/spark/transactions/infoquery)
* [`TransactionNotify`](/reference/spark/transactions/transactionnotify)
* [`Settlement`](/reference/spark/transactions/settlement)
* [`CancelTransaction`](/reference/spark/transactions/canceltransaction)
* [`TimeoutCallback`](/reference/spark/transactions/timeoutcallback)

<Note>
  **Pre-Authorization Only**

  Device Start currently only supports pre-authorization, for an option with Pre-Selection see [Remote Start](/docs/integrate-pos-device/spark/payment-flows/spark-remote-start).
</Note>

## Pre-Authorization Flow

To understand the device start pre-authorization flow, see the diagram below:

<Frame>
  <img src="https://mintcdn.com/nayax-44d6e37b/gp-udlFbAMEECcYg/images/docs/spark-device-start/image1.png?fit=max&auto=format&n=gp-udlFbAMEECcYg&q=85&s=4784e3d4b7eceb02fd17ace58eb12458" width="1759" height="1475" data-path="images/docs/spark-device-start/image1.png" />
</Frame>

Below is a breakdown of the diagram:

1. A consumer selects a service station (and/or presents a card) on the Nayax Device, which sends an [`InfoQuery`](/reference/spark/transactions/infoquery) request to the Nayax Server.
2. The Nayax Server sends a [`StartSession`](/reference/spark/transactions/startsession) to the 3rd Party Server.
3. The 3rd Party Server responds to the Nayax Server with a `StartSession Response`.
4. The Nayax Server sends an `InfoQuery` to the 3rd Party Server.
5. The 3rd Party Server responds to the Nayax Server with an `InfoQuery`.
6. The Nayax Server sends an `InfoQuery` command back to the Nayax Device.
7. The consumer presents their card (if they haven't already done so). An `AuthorizationRequest` is sent from the Nayax Device to the Nayax Server.
8. The Nayax Server performs authorization with a Payment Provider and then sends a [`TransactionNotify`](/reference/spark/transactions/transactionnotify) to the 3rd Party Server.
9. The 3rd Party Server responds to the Nayax Server with a [`TransactionNotify`](/reference/spark/transactions/transactionnotify) Response.
10. The Nayax Server sends an `AuthorizationResponse` back to the Nayax Device. At this point, the service can be provided on the Service Station, and the Nayax Device is back to idle.
11. The 3rd Party Server sends a [`Settlement`](/reference/spark/transactions/settlement) command to the Nayax Server.
12. The Nayax Server performs the settlement with the Payment Provider and then sends a [`Settlement`](/reference/spark/transactions/settlement) back to the 3rd Party Server.