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Microsoft interview notes, page 35 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

May 2026
Microsoft SWE interview that went deep on language model decoding. One question, but it had real teeth: implement greedy decoding and beam search from scratch given a next-token log-prob API. Not a leetcode grind, more of an applied algorithms design problem.
  • Given a function that returns log-probabilities for the next token given a prefix, implement both greedy decoding and beam search. Greedy should pick the highest log-prob token at each step and stop at EOS or max_len. Beam search should maintain the top-k candidate sequences by cumulative log-probability, expanding all beams each step and pruning back to k. Discuss edge cases like early-finished beams.

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

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Microsoft·Product Manager·Onsite - System Design / Architecture

May 2026
Microsoft PM interview with a single system design question. Pretty open-ended, not much else to go on.
  • Design a parking lot system.

“Classic question but it opens up fast once you start talking through it.”

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Microsoft·Software Engineer·Onsite - Product Sense / Strategy

May 2026
Microsoft data analyst interview with a classic product sense question dressed up as a history lesson. Just the one question from what I remember, no SQL, no case math, pure product thinking.
  • Imagine you invented 3M sticky Post-it notes. How would you determine whether there is a real market fit for this product?

“I went straight into listing customer segments and got a bit lost in my own answer.”

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Microsoft·Product Manager·Onsite - Product Sense / Strategy

May 2026
Interviewed for a PM role at Microsoft, got asked about subscription products. Pretty short and focused.
  • What is your favorite subscription-based product?

“Blanked for a second because there are too many obvious answers and I didn't want to just say Spotify like everyone else.”

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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 thing was centered on one big problem about change-data capture and diff persistence, which sounds focused but actually sprawls in a lot of directions once you start pulling on the threads.
  • Design a service that listens for database change notifications, computes the before/after diff for each change, and stores those diffs durably for downstream consumers. Cover schema design, notification reliability, ordering and idempotency, diff computation, storage model, and scalability.

“I started with the notification pipeline and that was probably the wrong call.”

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Microsoft·Product Manager·Onsite - Product Sense / Strategy

May 2026
PM interview at Microsoft, just one question about estimating Slack's daily message volume. Short and focused, felt more like a warmup than a full round.
  • Estimate how many Slack messages are sent globally per day.

“Classic estimation question.”

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Microsoft·Software Engineer·Technical Phone Screen

May 2026
Microsoft coding interview with a graph theory problem. Nothing too wild but the BFS angle took me a minute to fully work through.
  • Given a bidirectional graph with n vertices (labeled 0 to n-1) and a list of edges, find the length of the shortest cycle. Return -1 if no cycle exists.

“My first instinct was DFS and I started going down that path before catching myself.”

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Microsoft·Software Engineer·Onsite - System Design / Architecture

May 2026
Microsoft Applied Scientist interview with a pretty gnarly system design question around semantic code search. One question, real constraints, and I left feeling like I'd only half-answered it.
  • Design a service that indexes code embeddings (e.g., from a transformer-based code model) and returns the top-k most semantically similar code snippets for a query, with results in under 50 milliseconds.

“The latency constraint is what tripped me up.”

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Microsoft·Software Engineer·Onsite - System Design / Architecture

May 2026
Microsoft system design round for a software engineer role, focused entirely on building a rate limiter from scratch and then scaling it to 100K QPS. Pretty deep dive, more than I expected for a single question.
  • Implement a rate limiter with an allow(client_id, timestamp) method that returns true or false based on a configured policy like N requests per W seconds per client.
  • At 100K QPS, which per-client data structure would you choose: a deque of timestamps, fixed counters, or token bucket state, and why?
  • How would you handle in-process throughput at scale: lock-free atomics, per-key sharded locks, or something else?
  • If the rate limiter needs to run across multiple nodes, how do you coordinate state? Walk through the trade-offs between Redis-based approaches, local counters with periodic sync, and consistency vs. accuracy.
  • What's your approach to failure modes when the backing store is unreachable: fail-open or fail-closed?

“Started with sliding window log using a deque of timestamps, which felt clean but I knew they'd push back on memory.”

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Microsoft·Product Manager·Onsite - Product Sense / Strategy

May 2026
PM interview at Microsoft where they asked me to design a B2B customer support product from scratch. Pretty open-ended, which sounds fun until you're actually in it.
  • You're a PM at Microsoft. Design a B2B customer support product for enterprise customers.

“I jumped straight into features, which was a mistake.”

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