Nexmo Interview Questions
& Process

The process kicked off with a recruiter chat via Skype. Following that, I had to complete a Codility test, needing at least a 70% score. After passing the test, I had a technical interview on Skype where I was asked about language choices for new projects, the differences between SQL and NoSQL, and garbage collection. Then, I went for a face-to-face interview that had four rounds. The first round involved a developer asking whiteboard questions, including creating a LinkedList in Java and finding a node, then addressing circular lists and finding dependencies. The second question was about finding a missing number in a nearly full array of numbers from 1 to 100. The second interviewer presented a puzzle about climbing stairs with one or two steps at a time, relating it to the Fibonacci sequence. The third round was less pleasant with two interviewers, one being quite arrogant, asking about C++ vs. Java, heap vs. stack, the 'volatile' keyword, and string reversal. They also probed deeply into system design, asking about handling concurrent requests for payment IDs in a ConcurrentHashMap using Java's concurrent package. The final round was with the hiring manager, who asked me to design a task scheduler using a given set_timer function, ensuring all tasks are executed even if new ones overwrite the buffer. I couldn't finish this and was told to take it home. I eventually sent the solution, but received no feedback on the interview itself. After two weeks, I contacted HR and was told I lacked core Java competency and couldn't handle the 'architectural' questions.

I applied at Nexmo in early April and heard back about 8 days later. The whole thing took about 2 weeks. First, I had a phone interview where we mostly talked about my past jobs and what I'm looking for in a company and this position. It was a pretty chill call, I felt really comfortable talking to the Talent Acquisition Partner. To wrap up, they invited me for an in-person interview that same week. I ended up having two onsite interviews within a week and a half to meet the whole Talent Team. The office space itself is really modern, has that young, cool startup vibe. It was a little intimidating doing an interview with 4 people at once, but the vibe was open and informal, yet professional, so I felt fine. They let me know about the positive outcome just two days after my second interview.

The whole thing took about a week. First, I had a chat with recruitment over the phone, which was pretty chill. They then asked me to build a hangman app. The next day, I spoke with the head of tech via phone, mostly going over my CV and what I've done. Then came a four-hour onsite with three different groups. First up was the head of tech for two whiteboard exercises on collections and concurrency. After that, two tech leads and I had a casual chat about different technologies. Finally, an architect and I did a whiteboard session focusing on microservices and caching. I actually got the job offer before I even left the building, which was pretty neat. It was a good experience overall, everyone made me feel comfortable and not stressed.

I had a 2-hour interview with 4 different people. It mainly focused on how I would use the current systems to change the company's knowledge development. The process focused on technical questions about the internal systems more than anything else, which was unexpected since I don't work there, but they expected me to know everything as an L&D manager. They weren't even sure where the role would fit because they wanted me to do many things and report to three people. After the interview, they ghosted me without any communication about whether I passed or not. I even wrote to HR, but still nothing after a month. This gives you an idea of the kind of company that doesn't care about its employees at all.