Glassdoor users rated their interview experience at Castelion as 100% positive with a difficulty rating score of 4 out of 5 (where 5 is the highest level of difficulty). Candidates interviewing for Software Engineer and rated their interviews as the hardest, whereas interviews for Software Engineer and roles were rated as the easiest.
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I applied online. I interviewed at Castelion (Torrance, CA) in Aug 2025
Interview
Interview went smoothly but it was difficult. Few phone screening ( 30 minutes each) followed up with onsite technical onsite presentation. I also talked to CFO and answered some questions regarding my previous role
I applied online. I interviewed at Castelion (Torrance, CA) in Mar 2026
Interview
Loved the interview process. Pretty standard compared to other companies. You go thru 3 phone screenings, one with the HR/hiring personnel. This is very general talk about your experience. Then two different phone calls with Manufacturing leads. Here you go more in depth and technical on the job duties and your experience. Be ready to answer questions specific to you current role and be honest, if you don't know the answer just say it. You will do a panel presentation of about an hour, they will send you a topic but most likely will be about a project that highlights your experience and thought process. Be ready to present to an audience of 4-6 and to answer questions on the go. Lastly, you will have 1:1 with each of the panel attendees and this will also be very technical but more relax. Depending who is interviewing you, some questions will be about manufacturing, others about experience, others about specific product, etc.
Interview questions [1]
Question 1
Why castelion? were do i see myself in X amount of years? What are some of weaknesses and strengths? and a bunch of specific questions on decisions I took based on my presentation.
Was a two person panel asking various questions about computer architecture, CI/CD, and test automation. The interview lasted about an hour and I'm still waiting to hear back. Was a good interview process, just prepare for more technical explanations, rather than pure coding knowledge.
Interview questions [1]
Question 1
What are some differences between x86 and ARM architecture.