I remember the exact moment we decided to scrap the tab bar. It was a Tuesday in March, and I had 47 open tabs across three browser windows. The horizontal strip had collapsed into favicons I couldn't distinguish. I stared at it for a full minute, closed the laptop, and walked to the kitchen. When I came back, I opened a blank document and wrote one line: "Tabs are a solved problem that nobody actually solved."
The Vertical Leap
Moving tabs to the sidebar wasn't revolutionary on its own — other browsers had offered it as an option buried in settings. We made it the only view. Every tab lives in a space. Every space has a purpose. The mental model shifts from "I have 47 tabs" to "I'm in my work context right now." We shipped the first internal build in April. By May, nobody on the team had reopened their old browser.
"The best interface is the one that disappears. Tabs don't disappear — they just get smaller and more stressful."