SpaceX Software Engineer Full-time Phone Screen Interview

Role: Software Engineer, experienced hire
Result: Passed the phone screen

Report time: 9/16/2026

The interview began with a short introduction and a detailed discussion of a previous project. The interviewer asked how the project could be improved if it were rebuilt from scratch.

The coding task was Timestamped Telemetry Differences, which involved subtracting two timestamped telemetry streams. Important clarifications included:

• A timestamp might appear in only one stream
• Timestamps were ordered non-decreasingly
• Missing values had to be handled correctly

The follow-up discussion moved into late-arriving events in a production system. The candidate proposed reconciliation and was then asked how downstream users could distinguish an initial result from a corrected result.

The candidate passed the round.