Selenium automates browsers. That's it! What you do with that power is entirely up to you.

Selenium provides support for the automation of web browsers. It provides extensions to emulate user interaction with browsers, a distribution server for scaling browser allocation, and the infrastructure for implementations of the W3C WebDriver ...

A headless browser intended for use in testing web-based applications.

WebDriver compatible driver for HtmlUnit headless browser

Selenium automates browsers. That's it!