Went through the Linear loop for a senior backend role in February 2026, got to the final round. Going to write up the system design piece specifically since that's the one people seem most anxious about.
First, important framing: Linear does not use level titles like L5 or E5. They don't publish a public ladder in that format. From what I can tell, "senior" is senior. They're a small team (under 200 people in early 2026) so the scope conversation in the design round is more about the problem than about leveling signals.
The format. One system design session, 60 minutes. No shared doc. They use a whiteboard tool (I used Excalidraw in a shared browser tab, your interviewer may have a preference). You're expected to drive.
What I was asked. Something in the project-management-tooling space, as you'd expect. They care about: collaboration and real-time sync, offline/conflict resolution, API design for third-party integrations, and how you'd handle scale for something like a webhook fan-out system. I got a variant of "design the notification delivery layer for a project management product."
What they actually cared about. Not naming every AWS service. They wanted to understand how I thought about tradeoffs. Why queue vs. direct push. How I'd handle at-least-once delivery vs. exactly-once. They pushed back when I jumped to a solution without stating assumptions, which I think is the point.
Depth vs. breadth. They went deep on one subsystem rather than covering the whole architecture at a surface level. I spent the last 20 minutes doing a deep dive on the retry/backoff strategy for failed webhook deliveries. That felt intentional.
Prep advice. If you're coming from a larger-company environment, resist the urge to over-engineer. Linear's codebase is famously clean and opinionated. The interviewers seem allergic to "we'd add a service for that." Think about what you'd actually build with a small team that needs to ship.
Happy to answer questions on other rounds too.