> For the complete documentation index, see [llms.txt](https://browsify.gitbook.io/browsify-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://browsify.gitbook.io/browsify-docs/understanding-key-terms/what-is-a-visitor-id.md).

# What is a Visitor ID?

A **Visitor ID** is a unique identifier assigned to each visitor, allowing **Browsify** to track their behavior across sessions. It helps identify and block repeat offenders, even if they change IPs or devices.