Zen Browser review: Firefox fork with vertical tabs became my daily driver

A user who had stuck with Firefox as their default browser for years has unexpectedly switched to Zen Browser and called it the best browser they have ever used. The account was published in a personal blog by an author who previously had not considered Mozilla alternatives seriously.

The key difference in Zen Browser is the vertical tab bar. While working on an article, the author keeps documentation, research papers, YouTube videos, AI tools, and several blog posts open at the same time. In Firefox's horizontal tab bar, titles shrank so much they became unreadable, and finding the right page turned into a guessing game. In Zen Browser, tabs are listed down the side of the window, so titles remain legible and finding the needed page takes a single glance.

The author notes that vertical tabs feel more natural on a widescreen monitor. Most websites do not use the full screen width anyway, so using that side space for tabs makes practical sense. In Firefox, extra effort was needed to keep dozens of open pages under control, while Zen Browser simplified the process.

The first impression of Zen Browser, according to the author, came not from individual features but from overall comfort. The browser did not force a change in the established workflow; it adapted to the existing one. The interface stays clean and unobtrusive: everything is easy to find, and after a few days the browser became second nature because attention goes to work rather than the tool itself.

The author admits that they expected Zen Browser to be another useless Firefox alternative that would be uninstalled within days. Instead, the browser gradually became the default for all tasks, and Firefox stopped being the choice by default. Zen Browser is built on the Firefox engine but offers a different approach to interface organization, which the author considers underrated among modern browsers.