Bulb Software Engineer Interview Questions
& Process

The interview process involved a phone screen followed by a Geektastic task. It's worth noting that the task is peer-reviewed against criteria that seem to contradict its own text, and it's also run against hidden test cases. While Bulb is free to recruit as it wishes, this approach might reflect the day-to-day work environment there. I suspect clear communication might be an issue, painting a picture of a corporate nightmare disguised as a social enterprise, the worst kind imaginable. The contrasting reviews on Glassdoor seem to corroborate this; some people appear to be fully bought into the corporate culture, while others are clearly not a fan.

This was the best interview process I've been through. They were really clear about everything and gave great feedback. I felt confident in their evaluation no matter the outcome. It was cool to meet the CTO at the end. There were 4 stages, all with real Bulb engineers, not robots: First, a code challenge on Geektastic where you write code and tests for a Bulb energy problem in any language you want. Second, a system design interview where you design a system for a new Bulb energy feature without writing code, focusing on technical, organizational, and business aspects. Third, a competency interview about your experience building and delivering products, your operational approach, and your impact. Finally, an interview with the CTO to see if our values and cultural principles align.

I had an initial phone interview with Caroline, which was really pleasant. It covered standard questions and competencies, like asking why I was interested in Bulb. After that, I was invited for a face-to-face interview at their office in Spitalfields, which had a really cool space. I thought I prepared well for this interview. Even though it's mostly a customer-service job, the interviewer seemed more focused on my mental maths. I had to sum up lots of big numbers while the interviewer watched and checked my calculations with her phone's calculator. It felt like her mental maths wasn't any better than mine. Also, **BULB DOESN'T PAY FOR TRAVEL EXPENSES AT THIS STAGE**. As a student from Durham, I assumed I'd get reimbursed for the £90 train fare. I've been reimbursed before at other firms, even startups, so it's become normal for me. I think it's unprofessional that Bulb doesn't clearly state upfront that they don't cover travel costs.