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Microsoft interview notes, page 2 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·Software Engineer·Technical Phone Screen

Apr 2026
Microsoft SWE interview, technical phone screen focused on a trie-based autocomplete design problem. Pretty implementation-heavy for a phone screen, but the follow-up on complexity analysis is what actually tripped me up.
  • Implement a simplified autocomplete system: given a list of historical sentences, build a class that takes one character at a time and returns all sentences matching the current prefix. When the user types '#', add the completed sentence to the dictionary and reset the input. No need to rank results by frequency.

“I jumped straight to a trie which felt right, and the interviewer seemed fine with that direction.”

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Microsoft·Software Engineer·Onsite - System Design / Architecture

Apr 2026
System design round at Microsoft for a software engineer role, centered entirely on building a URL shortener from scratch. Pretty thorough scope, they wanted everything from code generation strategies to analytics pipelines.
  • Design a URL shortening service similar to TinyURL or bit.ly, covering both functional and non-functional requirements.
  • What are the trade-offs between different short-code generation strategies, such as hashing with collision handling versus base-62 encoding of an auto-increment ID versus a distributed counter approach?
  • How would you choose between a key-value store and a relational database for storing URL mappings, and what does your schema look like?
  • How would you design the caching layer to handle hot short codes efficiently?
  • How would you approach geo-distributed deployments and CDN-level redirects to minimize redirect latency globally?
  • How would you handle abuse prevention, including rate limiting and malware URL scanning?
  • Walk through how you would design an analytics pipeline to track click events on shortened URLs.
  • Estimate the storage requirements and queries per second for a realistic user base for this service.

“I started with the API surface (POST a long URL, GET to redirect) and that part went fine.”

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Microsoft·Product Manager·Onsite - Product Sense / Strategy

Apr 2026
Interviewed for a PM role at Microsoft and got a competitor analysis question that felt deceptively open-ended.
  • How would you assess the competitive landscape for a given product or project?

“I jumped straight into naming competitors and listing features, which in hindsight was pretty shallow.”

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Microsoft·Software Engineer·Technical Phone Screen

Apr 2026
A 45-minute Microsoft software engineer screen that came through a referral. Pretty standard structure: intro, some behavioral stuff, then a deep dive into resume projects.
  • Walk me through your background and experience.
  • Tell me about a specific project from your resume and the decisions you made during it.

“Standard opener, nothing surprising.”

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Microsoft·Product Manager·Onsite - Product Sense / Strategy

Apr 2026
Microsoft PM interview with a product design question framed around Facebook's news feed. Single question, pretty open-ended, felt like they wanted to see how you structure a decision between two competing feed experiences.
  • You're a PM on the news feed team. Design a system to decide whether to show an ad or a friend recommendation after every 20 posts in the feed.

“I went straight to user goals and revenue tradeoffs, which felt right, but I underweighted the actual system side of it.”

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Microsoft·Software Engineer·Technical Phone Screen

Apr 2026
Microsoft SWE interview with a pretty niche streaming/string processing problem. The question was technically specific and required knowing KMP or at least being able to reason about prefix-suffix overlap under time pressure.
  • You're receiving a stream of string chunks one at a time. Concatenate them and output every character that appears before a given stop token, but you can't buffer the whole stream first. The stop token might be split across two consecutive chunks. How do you implement this efficiently?

“The 'split across chunks' constraint is what makes this non-trivial.”

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Microsoft·AI Engineer·Technical Phone Screen

Apr 2026
Microsoft AI Engineer technical screen, heavy on ML fundamentals. Three big topics back to back and the depth expected was pretty serious. Came out feeling okay but not great.
  • Walk me through boosting versus bagging. How does each method work, what does each one reduce, and when would you actually choose one over the other?
  • How do you decide which model to go with when you have multiple candidates? Walk through your process including how you use validation data, what metrics you pick, and how you weigh complexity against performance.
  • Beyond a single aggregate metric, how do you decide if a model is actually good enough to ship?

“I knew the textbook answer (bagging cuts variance, boosting cuts bias) but stumbled when they pushed on *when* to pick one.”

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Microsoft·Software Engineer·Onsite - System Design / Architecture

Apr 2026
Microsoft system design round for a software engineer role, full hour on designing a Slack-like messaging platform. Pretty thorough coverage of everything from WebSocket architecture to storage tiering and cross-region replication trade-offs.
  • Design a real-time team messaging platform similar to Slack, covering core features like channels, threads, reactions, file uploads, presence, and notifications at scale.

“This is a beast of a question because it looks like one question but it's really about ten.”

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Microsoft·Software Engineer·Technical Phone Screen

Apr 2026
Microsoft SWE interview with a classic Boggle board problem. Short on details but the question itself is the whole story.
  • Given a Boggle board and a dictionary, find and print all dictionary words that can be formed on the board.

“This one took me a minute to even figure out where to start.”

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Microsoft·Product Manager·Onsite - Product Sense / Strategy

Apr 2026
PM interview at Microsoft, one question about OneSoc that I wasn't fully prepared for. Short but it made me think harder about operational product design than I expected.
  • How would you reduce alert fatigue in Microsoft OneSoc?

“I fumbled the setup a bit because I jumped straight into solutions without defining what alert fatigue actually means in a security ops context.”

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