---
title: "Identifying Visitors"
slug: "identifying-visitors"
updated: 2021-11-29T22:26:03Z
published: 2021-11-29T22:26:04Z
canonical: "onpremises.webtrends.help/identifying-visitors"
---

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

# Identifying Visitors

How to track visitors and visitor sessions.

#### Visitor Identification for Analytics

If you use Webtrends Analytics reporting, identifying visitors and tracking visitor sessions is relatively simple. When a user initiates a session with your application session, you can pass visitor identifying data to the WT.co_f parameter. If your application already provides a unique identifier for the visitor, you can pass this information directly to WT.co_f. If your application does not provide an identifier, you can request a visitor ID from the Webtrends data collection server using the Get Visitor Identifier method. When you use this method, the data collection server returns a unique ID based on the IP address of the device and a time stamp. You can then pass this ID in the wt.co_f parameter in the next request, when you use the Post Event Data method.

If you use a Webtrends-provided visitor ID, you can persist this information by storing it in a cookie or INI file, or using another method. Requests with no value for wt.co_f will use IP address and user agent information to identify visitors. This is a weak method of visitor identification, and is not recommended.

#### Visitor Identification for Visitor Data Mart

If you use Visitor Data Mart, you need to provide more information to effectively track visitor sessions. Visitor Data Mart requires both a visitor ID, such as WT.vtid or WT.co_f, and a session ID, WT.vtvs. The visitor identifier can be obtained using the Get Visitor Identifier method described above. The WT.vtvs parameter specifies a time stamp expressed in UTC or "epoch" time, which is equal to the number of milliseconds since January 1, 1970.