Anthropic Senior+ Performance / Infrastructure Software Engineer Interview Experience — Three Screens and an Onsite Invitation

The process up to my onsite invitation was as follows.

1. Recruiter: passed, then waited two days.
2. Hiring manager screen: passed, then waited two days.
3. Technical coding phone screen: passed, then waited nine days.
4. Onsite: scheduled.

The recruiter round was very formal at the beginning. They really probed why I wanted Anthropic and why I wanted to switch jobs now. After the recruiter seemed satisfied with my answer about Anthropic, the conversation became friendlier.

I then moved to the hiring manager screen and skipped the online assessment. The conversation was very casual. It started with my self-introduction, what I had been working on, and my career aspirations. It did not take the full allotted hour.

Next was the technical coding phone screen. The problem was distributed mode and median, given 10 nodes and 1,000 elements. For the mode, I clearly identified the network as the bottleneck, so the solution needed to minimize data movement as much as possible. I went into how collectives could be used optimally and what their shapes could be, such as a tree or ring. The strategy also changes depending on the data distribution, such as whether it is uniform or skewed. For the median follow-up, we only discussed it and did not code an implementation.

After nine days, I received the onsite invitation.

As a follow-up, I wanted to know what the system design and network debugging prompts below might entail. I copied them from my candidate portal, and it seemed that Anthropic no longer provided question numbers such as System Design Q1.

System Design

For this interview, the evaluation focuses on how I reason about scalable, performance-bounded systems under realistic constraints. It is less about reaching a particular right answer and more about how I explore the problem space, derive bounds from first principles, and reason about trade-offs between competing strategies.

Network Debugging

This is a role-playing exercise in helping to debug a production compute job that has a networking problem.