CircleCI shares their hiring process in their blog. And I can say that they really stand up to what they said by actions. Their interview process is one of the best I've had so far. Interviewers are well trained (knows how to interview) and the process finished within 3 weeks (Recruiter promised 3 weeks and I thought they didn't mean it)!

1. Recruiter meeting (30 minutes)
2. Hiring Manager
3. Technical interview
4. Macro Interview (system design)
5. Product, Culture and Process (behavioural)
6. Engineering Director Conversation (30 minutes)

Recruiter meeting

A short call with a recruiter to understand the interview process, company culture and how the team works in Japan. The recruiter was professional and friendly. So it gave me a very positive first impression.

Hiring Manager

It was more like a conversation than an interview, in a good way. The hiring manager is good at making you relax. This interview gives you a deeper overview of how the team works, including their collaborative and remote culture.

There will be a few questions to make sure you are a good fit and how you think about your past experience and your thought on their working culture.

Technical interview

This is a pure technical interview round. Because I was applying for a full-stack position, I was asked to design an API and did a small coding question (not too crazy).

Macro interview (system design)

I met with two engineers. I really enjoy their way of conducting system design. Instead of throwing you "Design a Twitter", they do it iteratively. They start with a simple question and add features to it. Interviewers were well prepared and they apparently want to hear different solutions from you. I tend to give too complex solutions to solve the problem but thanks to the interviewers, I managed to figure out a simpler solution. Collaborative!

Product, Culture and Process

A lot of behavioural interviews start with "tell me about a time...." but this wasn't true for CircleCI. They are interested in how do you work, your leadership experience and your past projects. I recommend you pick a story that can highlight your collaboration skills.

Engineering Director Conversation

This was a short conversation to wrap up the interview if you make it to this stage. The engineering director acts as closer to answering any questions and concerns I have.

Summary

So how to prepare for your interview for CircleCI. There isn't much to do to be honest, except being yourself. I don't think practice 200 LeetCode will help, but getting yourself prepare to express your thought and experiences might help.