Senior SDE Interview Questions at Microsoft

Published July 22, 2026 · Updated July 22, 2026

8 real Senior SDE interview questions asked at Microsoft. Covers Technical, System Design, HR rounds. Sourced from engineers who cleared the loop.

8 questions
224 upvotes
Rounds: 3
Top topic: system-design

Interview Signals — What Microsoft Asks Senior SDEs

Frequently Asked Topics
system-design2x
typescript1x
behavioral1x
dsa1x
domain1x
Interview Rounds
Technical5q
System Design2q
HR1q
Experience Level
2-5 years5q
4-8 years2q
1-5 years1q

All Senior SDE Questions Asked at Microsoft

Microsoft Medium Technical round 2-5 yearsJavaC++

Design a data structure that supports insert, delete, and getRandom in O(1) average time. Walk through your approach.

↑ 42 upvotes · 33 engineers asked this · Senior SDE
Microsoft Hard System Design round 4-8 yearsSystem DesignDistributed Systems

Design the "presence" feature in Teams/Slack — showing whether a user is online, away, or in a meeting — that scales to tens of millions of concurrent users with near real-time updates.

↑ 38 upvotes · 16 engineers asked this · Senior SDE
Microsoft Medium Technical round 2-5 yearsTypeScript

Explain the difference between a TypeScript interface and a type alias. Give a concrete case where only one of them can express what you need.

↑ 36 upvotes · 28 engineers asked this · Senior SDE
Microsoft Easy HR round 1-5 years

Describe a time you had to learn a completely unfamiliar codebase or technology quickly to unblock a critical deliverable. How did you approach it?

↑ 25 upvotes · 15 engineers asked this · Senior SDE
Microsoft Hard System Design round 4-8 yearsSystem Design

Design a notification system that can send push, email, and SMS, where a user's preferences determine which channels are used, and a failed channel should fall back to another.

↑ 23 upvotes · 11 engineers asked this · Senior SDE
Microsoft Medium Technical round 2-5 yearsC#

In C#, what is the difference between Task.Wait() and await? Why does calling .Wait() on the UI thread risk a deadlock in a way that await does not?

↑ 21 upvotes · 12 engineers asked this · Senior SDE
Microsoft Medium Technical round 2-5 yearsPython

Write a Python decorator @timed that prints how long a function took to execute, and explain how functools.wraps prevents it from breaking introspection.

↑ 20 upvotes · 11 engineers asked this · Senior SDE
Microsoft Medium Technical round 2-5 yearsJava

Rewrite this imperative loop using Java Streams: filter a list of orders for status "PAID", then sum their amounts. Explain one case where a stream would actually perform worse than the loop.

↑ 19 upvotes · 10 engineers asked this · Senior SDE

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Frequently asked questions

What topics does Microsoft ask Senior SDEs?
Common topics: system-design, typescript, behavioral, dsa, domain.
What rounds are there in Microsoft Senior SDE interview?
Reported rounds: Technical, System Design, HR.
What experience level does Microsoft hire Senior SDEs at?
Most reported experience: 2-5 years.