Valve Corporation Software Engineer Interview Questions
& Process

A recruiter who's been at the company a while reached out and handled most logistics until the front desk took over flight and hotel booking. The first step was a technical phone screen, about an hour long, where they asked me to implement atoi perfectly and some questions about my past experience to gauge my technical depth. Then, if I passed, I was flown out to interview onsite (though remote was an option). The onsite interviews involved pairs of interviewers, one senior and one less so, usually from teams I might join. About 10% seemed personable. The day started with two coding questions on a big whiteboard, where I solved the problems while working with the interviewers. A lunch interview followed, which felt awkward. After a break, I had a non-technical interview. Shortly after, two of my interviewers ended the loop early, giving feedback about insufficient technical depth and customer requirements gathering, suggesting I re-interview with more experience. I suspect it was a culture fit issue, though the office is cool. I think Valve, being small, might avoid hiring people who could disrupt their structure and incentives.

I tried to keep things general to avoid issues for employees. There was a small payment mix-up for the hotel, so I rented a car and did a bit of sightseeing while waiting. I arrived on time, but there was about a 40-minute delay, which honestly isn't too surprising lately. Everyone was friendly, but the general vibe felt stressed, making it tough to concentrate on the coding problems and give clear answers. Whiteboarding isn't my strong suit, so they were cool and let me use Notepad++ with screen sharing for the remote interviewers. I asked about how they define project leadership roles with each new interviewer, and got surprisingly different answers each time. I figured it was worth digging into since they advertise a flat, self-organizing structure, even though people naturally form hierarchies. They seemed a bit concerned or annoyed, which I get. The interview wrapped up after a call with Gabe. Just before that, I met someone who seemed really nervous and asked the same question a few times even after I answered. The question was about cloth simulation with fp math problems due to large distances from the origin. My initial thought was forward error analysis to pinpoint where errors creep in, and my second idea was to increase the time step until the simulation looked right. This is basically about issues with NLPs, which can take days or weeks to fix, and I'm not sure if the interviewer knew that. Gabe had a question I'm not going to share, but I was left unsure about the impression I made since it was audio-only.

Had 1 phone chat about my resume and what I've done. Then a lunch chat where we talked about past work and what areas/features I'd want to improve/contribute to any of Valve's products (both from a technical and business angle). Then a full day of on-site interviews: 3 sessions for design/coding, 1 session to discuss general topics outside my usual zone of expertise, and 1 lunch chat to gauge my general technical/business thinking, aptitude, and customer focus.