This is my account of getting through the senior fullstack loop at Microsoft's Israel office, for a team working on AI and cyber security.
I had ten years behind me, split between hands-on fullstack work and leading a team. The opening was a Senior Software Engineer (Fullstack) position in Herzliya, on a team that straddles AI and security.
Because the level was senior or lead, I figured that code which merely compiles would not be what they cared about. I expected the emphasis to land on architectural judgment, weighing options against each other, and dealing with practical engineering limits.
I split my preparation into coding, system design and behavioral. Here is how each part went, including what turned out to be useful and what was not.
For coding I stuck with a popular set of 150 curated problems and cycled through it again and again, until the patterns, data structures and best solutions came almost without thinking, hard ones included. I never tried to grind through 500-plus random problems. My reasoning was that with 45 minutes on the clock, an interviewer is not going to produce some bizarre over-engineered puzzle. They pick a bounded problem that checks a recognizable algorithm. Get the main patterns down thoroughly and roughly 95% of what shows up is a variation on them.
To get a mental template for designing whole systems, I mostly watched video lessons from an online system design course. The big-picture walkthroughs taught me the recurring kinds of systems quickly, so I did not need to work through every exercise by hand. I did still sketch a handful of scenarios on a whiteboard myself, to get comfortable with timing and layout. Besides that I reviewed fullstack basics: React internals, the JavaScript event loop, choosing between SQL and NoSQL, event streaming, and tidy API design.
Microsoft evaluates against its own set of competencies, but I shaped my STAR answers around Amazon's Leadership Principles. Amazon's list is long and detailed, which suited the purpose. For each of the 14-plus principles I wrote up a story with numbers in it, which left me with a wide pool of examples to draw on whatever behavioral or leadership question came my way.
The loop was a single dense day made up of three main rounds.
The first round was system design: build a bike-sharing service that works in real time. The interviewer wanted functional and non-functional requirements laid out right at the beginning, then spent most of the time on trade-offs. We talked about how frequently bikes should report their location, where database writes would become a bottleneck, and how to lock a bike once somebody reserves it.
Round two covered technical knowledge and my background, and I thought of it as the comfortable one. It combined fundamentals questions with a long look back at what I had built. I described a complex project that I had owned, and the interviewer kept pressing on each architectural decision, framework pick and trade-off that I mentioned. Your own resume should hold no blind spots, since they will test whether you truly grasp how systems you built years ago function underneath.
The third round was problem solving, i.e. coding, with a Group Anagrams variant. What counted was a tidy implementation and covering the edge cases.
Some advice for other candidates:
At senior level, showing maturity beats being fast. Speedy code alone will not carry you, because the interviewer is judging your reasoning rather than your typing. What they seem to look for is edge cases you flag without a nudge, scaling limits you bring up before anyone asks, and alternatives you compare out loud along with their costs.
Stick to the standard coding patterns. Rare, niche LeetCode problems are a poor use of time. The common top-150 style set, learned until it is automatic, leaves your head free during the actual coding round.
Prepare to justify decisions you made earlier in your career. The project discussion drills two or three levels beneath your first answer. Have a clear account of why you chose a given technology or database schema, where it fell short, and what you would do differently now.
Discussion
Loading comments…