# Anonymous purchase data

Contacts are core to Airship, but we also collect a large amount of data from other sources which are associated to the contact. We can use that additional information to act as a unique identifier for the contact, so if we see some data from another source (i.e. Purchase data), which has a unique voucher code associated, providing airship issued that voucher, we can use this to tie the transaction back to the customer from the POS.

Fields we can use to associate purchase information to a contact include;

* Booking reference
* Loyalty Card number / Loyalty Membership reference
* Gift card number
* Unique voucher code
* Booking - Table number

Depending on your POS, and its capability - not all of these touch points may be available to link to a customer. Airship will require at least 1 of the above in order to associate any purchase to a contact.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://developers.airship.co.uk/basics/anonymous-purchase-data.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.