# Contacts Contacts are the basis of all customer data in Airship. Contacts records can store all sorts of data such as contact information and personal details. A contact record can also have any number of transactional records attached to them to represent a contact's timeline of interactions. For example, Table Bookings, WiFi interactions, Feedback, Purchase History and more. ### Contact merging Airship automatically merges contact records together based on unique customer identifiers. These identifiers are `email` or `mobile_number`. In other words, if you write a contact to us with an email address or mobile that already exists as part of a contact on Airship, we'll automatically update and/or append the data you send to the pre-existing contact record. --- # 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/contacts.md?ask= ``` 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.