SigmaOS

SigmaOS treats the browser like a to-do list. Every tab is a "task" that you can mark as done, clearing it from your workspace. This subtle psychological shift encourages you to close tabs and finish tasks rather than letting them pile up indefinitely.

Navigation is designed to be almost entirely keyboard-driven. You use single-key shortcuts to open pages, split the screen, or send links to different workspaces. It includes "Airis," an AI assistant that can rewrite text or summarize pages in context, further speeding up workflows.

It requires a significant shift in mindset; if you prefer clicking tabs with a mouse, SigmaOS will feel alien. But for keyboard-centric users who view browsing as a series of tasks to be completed, it offers a uniquely productive and focused environment. One caution: SigmaOS has not shipped an update since February 2025, so check that it is still being developed before you build your workflow around it.