Did my Notion frontend engineer interview loop in March 2026. L4 equivalent. Writing this up because most of the prep advice I found was generic SWE content and the frontend-specific stuff was thin.
Notion's product is famously complex on the frontend. Their editor is one of the most technically sophisticated pieces of web software out there. So they do actually care about frontend depth, not just whether you can useState your way through a todo app.
The rounds:
Phone screen was a standard Leetcode medium. Nothing frontend-specific, just an algorithmic problem. A little anticlimactic given the role.
Virtual onsite had 4 rounds:
Frontend technical (90 min): This was the real test. We started with a browser/DOM question and moved into performance. I was asked to debug a specific re-rendering problem (they gave me a component tree with a real perf issue), explain the root cause, and then talk through how React's reconciler works. Not "what is useMemo" level. More like: given this specific situation, what's happening in the fiber tree and what's your fix. I also got a question about event delegation and how you'd approach drag-and-drop without a library.
System design (60 min): They asked me to design a collaborative text editor. Yep. Very on-brand. I talked through operational transforms vs CRDTs, why CRDTs are appealing for a distributed system, and what the tradeoffs are on the client-side for rendering and cursor sync. I'm not an expert in CRDTs but knowing enough to have an opinion landed well. They're not expecting you to have built one.
Coding (45 min): More algorithmic. I got a medium graph problem. Standard prep covers this.
Behavioral (45 min): Standard STAR questions. One interesting one: describe a time you pushed back on a product decision because of a technical constraint. They wanted to see how you communicate tradeoffs to non-engineers.
What I'd prep differently: Read more about how browser rendering pipelines work, not just React internals. I got a question about layout vs paint vs composite that I answered but could have gone deeper. And genuinely use Notion's product and think about edge cases. Some of the questions felt like they came directly from real problems the team had worked on.
The vibe overall was collaborative. Nobody was trying to stump me. But they do want frontend engineers who care about how browsers actually work, not just framework-level stuff.