Basis Ai·Software Engineer·Onsite - System Design / Architecture
May 2026
System design round at Basis AI for a software engineering role, paired with a PM interviewer which I did not expect. The question was deliberately underspecified and that threw me more than I'd like to admit.
- Design a mobile app that recommends activities to travelers during an airport layover, given that the interviewer provides almost no requirements upfront.
- What is the core constraint that makes layover recommendations uniquely dangerous, and how should it shape the system's design?
- Walk through the recommendation pipeline from candidate generation to what the user actually sees.
- A user's flight gets delayed by 90 minutes while they are mid-activity. How does the system detect this and update its recommendations in real time?
- Your walking-time estimates turn out to be systematically too optimistic and users report nearly missing flights. How do you detect this from telemetry and fix the model?
- A merchant pays for placement in the recommendations. How do you design the ranking so paid placement can influence results without ever surfacing an unsafe or irrelevant option, and how do you prove to the business it isn't hurting trust?
- How does your feasibility model change for a long international layover where the traveler must re-clear immigration and security to leave the terminal?
“I jumped straight into components and the interviewer just watched me flounder for a bit before nudging me.”