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Microsoft interview notes, page 20 of 60

FAANG / Big Tech

Most of these Microsoft write-ups come from Software Engineers (372), then Product Managers (124) and Machine Learning Engineers (53). The most reported rounds are the technical phone screen (255), the product sense round (111), the system design round (93) and the behavioral / leadership round (49).

597 interview notes · updated Oct 2026

Microsoft·Data Scientist·Technical Phone Screen

May 2026
Phone screen for a Data Scientist role at Microsoft, pretty much all behavioral with a couple of quick questions about programming languages tacked on at the end. Nothing technically deep, but the behavioral side required some real prep if you wanted to give structured, quantified answers.
  • What was the most challenging project you've worked on, and what made it so difficult?
  • Walk me through a challenging project: what was your approach and what came out of it?
  • Tell me about a time you had to work with a difficult team. How did you handle it?
  • Describe an obstacle you faced in pursuing your career goals.
  • Why do you want to work at Microsoft specifically?
  • What programming language are you most comfortable with, and what's your second?

“I had an answer ready but I kept second-guessing whether my 'challenge' sounded impressive enough.”

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Microsoft·Software Engineer·Technical Phone Screen

May 2026
Microsoft SWE interview, got asked to implement an LRU cache. Pretty standard but the details trip you up if you're not careful.
  • Implement an LRU (Least Recently Used) cache with get and put operations, both in O(1) time.

“I knew the answer going in but still fumbled the doubly linked list pointer updates under pressure.”

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Microsoft·Software Engineer·Onsite - System Design / Architecture

May 2026
Microsoft system design round focused on building a cloud console home page, with a heavy emphasis on auth, permissions, and audit logging. The scope was broader than I expected and I spent way too long on the login flow before realizing they wanted me to go deeper on the multi-tenancy and audit pipeline pieces.
  • Design the end-to-end flow from a user logging in to seeing their personalized cloud console home page, including how authentication and session handling work.
  • How would you enforce multi-tenancy isolation so that a user can never see resources belonging to a tenant they don't have access to?
  • Walk through how you'd implement role-based access control, including support for resource-scoped or project-scoped roles, not just global roles.
  • What would your audit logging pipeline look like: what events do you log, where do the logs go, and how do you make them tamper-resistant and queryable?
  • How would you design the home page data aggregation to meet a p95 latency target under 500ms, given that the page pulls from multiple backend services?

“I started with the standard OAuth/OIDC flow and felt pretty solid there, but then they pushed on token storage, refresh token rotation, and what happens if a token is compromised mid-session.”

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Microsoft·Technical Program Manager·Onsite - System Design / Architecture

May 2026
TPM interview at Microsoft with a single product/system design question. Short session, left me wondering if I'd said enough.
  • Design a kitchen.

“I went straight to users and use cases, like who's cooking, what scale, residential vs commercial.”

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Microsoft·Software Engineer·Technical Phone Screen

May 2026
Microsoft SWE interview with an array filtering problem that looks straightforward until you hit the tie-breaking edge case. The problem itself was clean but the devil was in the details around duplicate handling.
  • Given a list of integers and a value k, return a new list containing only the k largest elements, preserving their original order. Duplicates count separately, and if values are tied at the boundary, keep the leftmost ones to hit exactly k elements.

“The basic case I got pretty quickly.”

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Microsoft·Software Engineer·Onsite - System Design / Architecture

May 2026
System design round at Microsoft for a software engineering role. The whole session was basically one big question about designing YouTube's live stream comment system, and it went deep fast.
  • Design the comments and live chat system for YouTube live streams, covering real-time fan-out to millions of viewers, moderation, rate limiting, history scrollback, and graceful degradation under traffic spikes.
  • Why would you choose Kafka over other message queue systems for the ingestion and fan-out layer here?
  • How would you shard the system per stream, and what's your strategy specifically for streams that suddenly go viral or hit millions of concurrent viewers?
  • How do you ensure moderation actions (bans, comment removals) are durable and applied consistently across all viewers in real time?

“This question sprawls in every direction if you let it.”

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Microsoft·Software Engineer·Onsite - Coding / Algorithms

May 2026
Microsoft SWE coding round, one question the whole time. The problem looked like a simple array scan but the full-price tracking part tripped me up more than I expected.
  • Given a prices array, compute each item's final selling price by finding the first later item with a price less than or equal to it and subtracting that value as a discount. Output the total of all final prices and the indices of items sold at full price.

“The core scan isn't bad once you think monotonic stack, but I got snagged on the output format.”

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Microsoft·Software Engineer·Technical Phone Screen

May 2026
Microsoft SWE interview with a graph problem that sounds straightforward until you actually sit down with it. One question, tree/graph territory, no behavioral stuff mentioned.
  • You're given a directed graph that was originally a rooted tree of N nodes (values 1 to N), with exactly one extra directed edge added. Given the edge list, find and return an edge that can be removed to restore it to a valid rooted tree. If multiple valid answers exist, return the one that appears last in the input array.

“This one took me a minute to even parse correctly.”

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Microsoft·Data Scientist·Technical Phone Screen

May 2026
Microsoft data scientist interview with a meaty end-to-end ML case study on a customer purchase prediction problem. One question, but it had about five sub-questions buried inside it, so budget your time accordingly.
  • You ran a marketing campaign to 10,000 customers and 500 purchased (5% conversion rate). Walk through your full approach to building a model that identifies which customers are most likely to buy, covering feature engineering, handling class imbalance, threshold selection, validation strategy, and feature selection.

“This is a monster of a question and I kind of underestimated how many pieces they actually wanted covered.”

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Microsoft·Product Manager·Onsite - Product Sense / Strategy

May 2026
Interviewed for a PM role at Microsoft and got asked about my overall product management philosophy. Pretty open-ended and I wasn't totally sure how deep they wanted me to go.
  • What is your philosophy of Product Management?

“I rambled a bit.”

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