Microsoft system design interview

Questions Microsoft asks in this round 58

• 

  Design a rate limiterSystem designDesign a service that limits how many requests each API client can make. It sits in front of every API endpoint at high traffic.

  Last asked Apr 2026Were you asked this too?
• 

  Design TinyURLSystem designTurn long URLs into short links and redirect visitors fast, at billions of redirects a day, with optional custom aliases and expiry.

  Last asked Jun 2026Were you asked this too?
• 

  Design a distributed key-value storeSystem designStore and serve billions of keys with low latency, partitioned across machines and replicated to survive failures, with tunable consistency.

  Last asked Jun 2026Were you asked this too?
• 

  ML design for retrieval: embeddings, hybrid search and rankingML designDesign the machine learning behind the retrieval stage of a question-answering system. Discuss how you train the embedding model, how retrieval combines dense and keyword search…

  Last asked Mar 2026Were you asked this too?
• 

  Design a ticket booking systemSystem designSell seats for concerts and games where demand spikes the moment sales open: hold seats briefly, never sell one twice, and stay up under the rush.

  Last asked Feb 2026Were you asked this too?
• 

  Design a lab machine fleet monitor with remote rebootSystem designDesign a service that watches a fleet of lab machines running compute workloads. Each machine polls the service for work; a work item names a payload the machine must download…

  Last asked Sep 2026Were you asked this too?
• 

  Design a global one-to-one voice calling systemSystem designDesign voice calls between registered mobile users worldwide, at millions of users. A caller rings another user, the callee gets an incoming-call notification and accepts or…

  Last asked Sep 2026Were you asked this too?
• 

  Design a voice and chat AI receptionist for businessesAI systemBusinesses want an AI receptionist that answers their phone number and chats on their website, app and messaging channels. It answers from information the business has approved…

  Last asked Sep 2026Were you asked this too?
• 

  Latency got worse right after a deploy: what do you do?System designA new version went out and 10 to 15 minutes later latency or reliability is degrading. Explain how you would notice, how you decide whether to roll back right away or investigate…

  Last asked Sep 2026Were you asked this too?
• 

  Design a nearby points-of-interest serviceSystem designGiven a user's location, return the closest restaurants, shops and other places of interest within a radius, fast, for a read-heavy global audience.

  Last asked Sep 2026Were you asked this too?
• 

  Design an OS notification platform, working with an AI assistantSystem designDesign the notification system of a desktop operating system: the platform piece that lets many applications raise notifications and shows them to the user. Cover the app-facing…

  Last asked Sep 2026Were you asked this too?
• 

  Predict employee attrition and explain what drives itML designYou get an HR dataset with one row per employee (age, job role, monthly income, overtime and similar columns) and a label saying whether the person left. Build a model that…

  Last asked Aug 2026Were you asked this too?
• 

  Design an incident ticket correlation platformSystem designDesign a platform that takes in a high volume of incident tickets and alerts at the same time and groups the ones caused by the same underlying problem, so responders see one…

  Last asked Aug 2026Were you asked this too?
• 

  Design trackable product links that reward every Nth visitorSystem designCompanies create and edit product pages with images and descriptions, generate unique links to share on social media, and see each link's reach and engagement. The platform also…

  Last asked Aug 2026Were you asked this too?
• 

  Design an online tic-tac-toe service over REST, with matchmakingSystem designTwo players are matched online and play tic-tac-toe from their own devices. Clients may only talk to the server through REST APIs, and the service runs in several regions. Design…

  Last asked Aug 2026Were you asked this too?
• 

  Design log storage with live tailing of growing filesSystem designProducers keep appending records to log files at very high volume. Store them durably and let users read files back, including users who read a file while it is still being…

  Last asked Aug 2026Were you asked this too?
• 

  Design a metrics monitoring systemSystem designCollect metrics from every host and service, store them as time series, power dashboards over months of data, and alert when thresholds are crossed.

  Last asked Jun 2026Were you asked this too?
• 

  Sort a 500 GB CSV by one column with 16 GB of RAMSystem designA CSV file of about 500 GB must be sorted by one of its columns on a machine with 16 GB of memory. Describe the external merge sort: cutting the file into chunks that fit in…

  Last asked Jun 2026Were you asked this too?
• 

  Design a distributed web crawlerSystem designCrawl billions of web pages politely and repeatedly, deduplicating URLs and content, to feed a search index or a training-data pipeline.

  Last asked May 2026Were you asked this too?
• 

  Design personalization memory for a chatbotAI systemDesign how an AI assistant remembers things about each user across conversations and uses them to personalize answers. Cover what to store and how it is extracted, retrieval at…

  Last asked May 2026Were you asked this too?
• 

  Design a low-latency product price update APISystem designDesign an API that updates the prices of specific products and makes the new prices visible quickly to everything that reads them. Cover the write path, how readers and caches…

  Last asked Apr 2026Were you asked this too?
• 

  Design typeahead suggestionsSystem designSuggest completions as the user types into a search box, within tens of milliseconds, ranked by popularity and fresh with trending queries.

  Last asked Apr 2026Were you asked this too?
• 

  Design a personalized search ranking systemML designRank search results for each user's query and context so they find and book (or order) what they want, learning from clicks and conversions.

  Last asked Apr 2026Were you asked this too?
• 

  Design re-engagement notifications for inactive usersSystem designDesign a system that brings back users who stopped using an AI assistant product: decide who to contact, when and over which channel, what to say, how often, and how to measure…

  Last asked Apr 2026Were you asked this too?
• 

  Design a secure API for an AI assistantSystem designDesign the API through which clients call an AI assistant, with the focus on security. How are callers authenticated, how are tokens issued, signed and validated, how is each…

  Last asked Apr 2026Were you asked this too?
• 

  Design a Slack-like chat systemSystem designWorkspaces, channels, threads and direct messages with real-time delivery, unread state, search and history, for large companies.

  Last asked Feb 2026Were you asked this too?
• 

  Design an online chess gameSystem designMatch players of similar rating, play live games with clocks, handle disconnects and reconnects, and keep game history and ratings.

  Last asked Feb 2026Were you asked this too?
• 

  Clean OCR output into a training dataset for an LLMML designYou have a large amount of text produced by OCR. Design the pipeline that cleans it and turns it into a dataset for training a language model: fixing or dropping garbled text…

  Last asked Feb 2026Were you asked this too?
• 

  Design a distributed rate limiterSystem designDesign a rate limiter that enforces a token-bucket limit per client across a fleet of servers. Cover where the limiter sits, where the bucket state lives (a shared store, local…

  Last asked Feb 2026Were you asked this too?
• 

  Design a job scheduler for ETL pipelinesSystem designDesign a system that runs ETL jobs on schedules and as dependency graphs: defining pipelines, triggering, distributing work to workers, retries, backfills, monitoring and avoiding…

  Last asked Feb 2026Were you asked this too?
• 

  Design a video vision-language model end to endML designDesign a model that understands video and answers questions about it in language: data and its labels, frame sampling and the video encoder, how visual tokens reach the language…

  Last asked Feb 2026Were you asked this too?
• 

  Design a read-heavy service for org chart subordinate countsSystem designGiven manager-report relationships for a company, answer "how many people are under this person?" for any employee, at high read volume. Then handle changes: when a reporting…

  Last asked Feb 2026Were you asked this too?
• 

  Design a distributed job schedulerSystem designDesign a service that runs millions of scheduled and on-demand jobs (cron-like and one-off) reliably across a fleet of workers.

  Last asked Jan 2026Were you asked this too?
• 

  Design a database that tracks changes to resourcesSystem designDesign a store that records every change to a set of resources so users can see a resource's history and its state at any past time. Cover the data model, writes, queries over…

  Last asked Jan 2026Were you asked this too?
• 

  Design REST APIs for storing JSON filesSystem designDesign the REST API and the backend for a service that stores and serves JSON documents: resource paths, methods, versioning, partial updates, concurrency control, large files and…

  Last asked Jan 2026Were you asked this too?
• 

  Shard a large input embedding table across devicesML designA model's V, H input embedding table is too big for one device. Compare sharding along the vocabulary with sharding along the hidden dimension: how a lookup works in each, the…

  Last asked Jan 2026Were you asked this too?
• 

  Shard an LM head and combine the logitsML designThe output layer maps a hidden state through an H, V weight matrix to vocabulary logits. Compare splitting the weight by vocabulary with splitting it by hidden dimension: what…

  Last asked Jan 2026Were you asked this too?
• 

  Design email ranking and summarization for an inboxAI systemDesign features that rank a user's incoming email by importance and summarize messages and threads with a language model. Cover signals for ranking, training labels, the…

  Last asked Jan 2026Were you asked this too?
• 

  Infer a user's intent from their typing in real timeML designAs a user types into an assistant or search box, predict what they intend to do so the product can respond early. Cover labels and data, features from partial input, the model and…

  Last asked Jan 2026Were you asked this too?
• 

  Make LLM output match a word processor's formattingAI systemA writing assistant inside a word processor generates text that must fit the document's formatting: styles, headings, lists, tables. Design how you get the model to produce…

  Last asked Jan 2026Were you asked this too?
• 

  Reward-model RLHF versus direct preference optimizationML designWalk through a classic RLHF pipeline: supervised fine-tuning, a reward model trained on preference pairs, then policy optimization (PPO) with a KL penalty to the reference model…

  Last asked Jan 2026Were you asked this too?
• 

  Design a cloud console's main page after sign-inSystem designDesign what happens when a user signs in to a cloud service's console and the main page is built: authentication, loading the resources the user may see, permission checks, audit…

  Last asked Dec 2025Were you asked this too?
• 

  Design an image sharing service that stores each file onceSystem designDesign a service where users upload, view, download and delete images, and identical images are stored only once, keyed by a content hash. Explain how metadata and blobs stay…

  Possibly retiredWere you asked this too?
• 

  Design a hotel booking systemSystem designSearch hotels by place and dates, show availability and prices, and book rooms without double-booking, including holds and cancellations.

  Were you asked this too?
• 

  Design a Kafka-like distributed message queueSystem designDesign a durable, partitioned log that producers append to and many consumer groups read at their own pace, surviving broker failures without losing acknowledged messages.

  Were you asked this too?
• 

  Design a notification systemSystem designA shared service other teams call to send push, email and SMS notifications: templates, user preferences, retries, deduplication and rate limits.

  Were you asked this too?
• 

  Design a payment systemSystem designAccept card payments for merchants: authorize, capture, settle with card networks, and reconcile, never charging twice or losing money.

  Were you asked this too?
• 

  Design a quota serviceSystem designTrack and enforce how much of each resource (API calls, storage, compute) every tenant may use, with fast checks and limits that stay accurate across regions.

  Were you asked this too?
• 

  Design a top-K popular items systemSystem designReport the K most viewed or played items over sliding windows (last minute, hour, day) from a firehose of billions of events per day.

  Were you asked this too?
• 

  Design a VM bandwidth rate limiterSystem designCap the network bandwidth each virtual machine in a cloud region may use, enforcing per-tenant limits across many hosts without adding latency to packets.

  Were you asked this too?
• 

  Design Amazon LockerSystem designLet customers pick a locker location at checkout, assign a compartment that fits the package, and give them a code to collect it within a few days.

  Were you asked this too?
• 

  Design an online game leaderboardSystem designShow the top players and each player's own rank in real time as millions of scores update.

  Were you asked this too?
• 

  Design DropboxSystem designSync files across a user's devices and shared folders: upload large files reliably, transfer only what changed, and handle conflicting edits.

  Were you asked this too?
• 

  Design Facebook MessengerSystem designOne-to-one and group messaging for a billion users: real-time delivery, offline sync, read receipts and message history on every device.

  Were you asked this too?
• 

  Design Google DocsSystem designMany people edit the same document at once and see each other's changes and cursors live, with offline edits and full version history.

  Were you asked this too?
• 

  Design Google NewsSystem designGather articles from thousands of publishers, group stories about the same event, and show each reader a fresh, personalized front page.

  Were you asked this too?
• 

  Design InstagramSystem designUsers post photos and videos, follow each other and scroll a feed; design upload, storage, feed generation and serving media worldwide.

  Were you asked this too?
• 

  Design SpotifySystem designStream music to hundreds of millions of listeners: catalog, search, playlists, smooth playback over bad networks, and offline downloads.

  Were you asked this too?