---
title: "Contact identifier"
slug: "contact-identifier"
abstract: "Overview of the contact identifier in xDB Data Migration Tool."
---
# Contact identifier

A contact identifier is created for the identifier on the Sitecore 8.x contact.

|     |     |
| --- | --- |
| Source object | Document from the `Contacts` collection in the MongoDB database |
| Property on source object | `Identifiers.Identifier` |
| Target object | `Sitecore.XConnect.ContactIdentifier` |
| Contact identifier source | `xDB.Identifier` |
| Contact identifier level | `Known` |
| Mapping definition | MongoDB to xConnect Contact Mappings > MongoDB Contact Identifier to xConnect Contact Identifier Constructor |