Microsoft Software Engineer interview questions

372 Software Engineers have shared notes from their Microsoft interviews, with the questions they were asked in each round. That is 62% of the 597 Microsoft interview notes on Screna AI.

372 Software Engineer interview notes

Microsoft·Software Engineer·Onsite - Multi Round

Sep 2026
Went through three rounds of entry-level SDE interviews at Microsoft in the US, covering DSA, object-oriented design, system design, and CS fundamentals. Pretty well-rounded process, nothing too wild but the follow-ups kept things interesting.
  • Clone a linked list that has both next and random pointers.
  • What is the difference between authentication and authorization?
  • Explain the core principles of object-oriented programming.
  • Design a parking lot system, including classes, relationships, and how components interact.
  • Implement an LRU Cache from scratch.

“The base problem is manageable if you've seen it before.”

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Microsoft·Software Engineer·Online Assessment (OA)

Sep 2026
Internal transfer loop at Microsoft for an SDE role, same level. The process included a HackerRank OA, a system design component, and a behavioral round, though the OA ended up being cancelled before the candidate even sat it.
  • What is the typical format of a 75-minute HackerRank assessment at Microsoft, including number of questions, difficulty level, and whether MCQs or SQL appear?
  • Which algorithmic patterns come up most frequently in Microsoft coding assessments, and is focusing on hash maps, two pointers, sliding window, intervals, BFS/DFS, heaps, and stacks the right call?
  • How do hidden test cases and time limits work on HackerRank, and is partial credit actually given for incomplete solutions?
  • For an internal candidate, what depth is expected in a system design interview and is it more conversational or a structured whiteboard-style session?
  • In a behavioral or 'AA' round, can the conversation turn technical or is it purely leadership and values-based?

“I kept going back and forth on whether to expect two mediums or a mix with an easy thrown in.”

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Microsoft·Software Engineer·Online Assessment (OA)

Sep 2026
Applied for a Microsoft SWE summer internship and just wrapped up the OA. Two coding problems, one manageable and one that exposed some gaps in my algorithms prep. Now sitting here wondering if partial credit is enough to move forward.
  • Solve a coding problem at roughly easy difficulty level, passing all test cases.
  • Solve a harder coding problem requiring you to select the right data structure under time constraints.

“Got through this one clean.”

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Microsoft·Software Engineer·Online Assessment (OA)

Aug 2026
Ran into an AI-assisted coding problem on the Microsoft SWE intern HackerRank OA and started wondering what companies are actually evaluating when they watch how you use the AI tools.
  • What are companies actually looking for in how candidates use AI assistance during an online assessment?

“Second problem on the OA had AI assistance baked in and i genuinely had no idea if i was supposed to lean on it or treat it like a crutch to avoid.”

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Microsoft·Software Engineer·Online Assessment (OA)

Aug 2026
Took the Microsoft new grad OA and had a rough time. First problem clicked, second one did not, and now I'm sitting here wondering if partial credit is a thing.
  • Given an array, solve a problem using a prefix sum approach.
  • Solve a greedy array problem involving minimum and maximum constraints.

“Got this one fully.”

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Microsoft·Software Engineer·Onsite - Multi Round

Jul 2026
Went through three technical rounds at Microsoft for a senior role, 7 years in. DSA felt strong, system design was the weak link and I knew it walking out.
  • Design a scalable system, covering reliability and fault tolerance.
  • Solve an algorithmic problem, then discuss how your solution would hold up at scale.
  • Solve a second algorithmic problem with follow-up questions on scaling and edge cases.

“Covered scaling, reliability, and idempotency but completely blanked on caching.”

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Microsoft·Software Engineer·Technical Phone Screen

Jul 2026
Phone screen for a Software Engineer role at Microsoft where they handed me an AI-written URL shortener and asked me to tear it apart. Decent question, though I'd say the follow-ups were where it got genuinely hard.
  • You're given an AI-generated in-memory URL shortener implementation. Walk through the bugs and correctness issues in both the shorten and resolve methods, explain why each is a problem, and describe how you'd fix them.
  • How would you write a unit test that deterministically reproduces the collision bug in the code generator?
  • If this service had to run across multiple processes or servers, which assumptions in the current in-memory design break and what would you change?
  • How would you make the code generation both collision-resistant and unguessable at the same time?
  • If the url_to_code reverse map was removed entirely, what behavior changes and does that fix or remove any of the existing bugs?

“The collision bug in shorten is the obvious one, and I spotted it pretty quick.”

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Microsoft·Software Engineer·Technical Phone Screen

Jul 2026
Microsoft SWE interview with a string assembly problem that escalated across three parts. Each follow-up added a new wrinkle and by Q3 I was scrambling to keep my graph logic clean.
  • You have a list of fragments, each with a start tag, end tag, and payload string. Fragments chain together when one fragment's end tag matches the next fragment's start tag. Given that the fragments form exactly one continuous chain, assemble and return the concatenated payload string.
  • Now treat each fragment as bidirectional. You can traverse the chain forward or backward, and either ordering of the payloads is a valid answer. Modify your solution to handle this.
  • The input may now contain multiple disjoint chains. Each group of fragments forms its own independent chain with no branching. Return all assembled strings, one per chain.

“Felt straightforward at first.”

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Microsoft·Software Engineer·Technical Phone Screen

Jul 2026
Microsoft SWE interview with a graph/tree problem that looks deceptively clean until you actually try to implement it. One question, but it had enough edge cases to keep me busy.
  • You're given a list of directed edges that originally formed a rooted tree, but one extra edge was added. Find and return the edge to remove so the graph becomes a valid rooted tree again. If multiple candidates exist, return the last one in the input.

“I knew union-find was involved but kept second-guessing myself on the two-case split: when a node ends up with two parents vs when there's a cycle but no double-parent.”

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Microsoft·Software Engineer·Technical Phone Screen

Jul 2026
Microsoft SWE interview with a grid-based BFS problem. Pretty standard algorithmic round but the problem had enough edge cases to keep you honest.
  • You're given a 2D grid where cells are either walls, gates, or empty rooms. Fill each empty room with its shortest distance to any gate, moving only up/down/left/right. Walls and unreachable rooms stay as-is.

“My first instinct was to BFS from every empty room individually and find the nearest gate.”

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