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 Jan 2026
Google system design interview
Round 6 of 8 · 44 questions reported
- Length
- 45 min
- Format
- Whiteboard for the diagram, a doc for requirements and capacity math
- Heads-up
- From L5 (some L4 loops too); staff loops have two, one infrastructure and one product.
Questions Google asks in this round 44
- 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.Last asked Jan 2026
- Design LLM review summaries that resist prompt injection and PII leaksAI systemBuild a platform that takes customer product reviews from an online store and has a large language model summarize them for an internal dashboard. The round centered on trust and…Last asked Oct 2026
- Design a CI/CD systemSystem designOn every commit, build and test the code on a fleet of workers, then roll it out to production safely, with logs, retries and rollbacks.Last asked Sep 2026
- Design an offline-first client that syncs edits across devicesSystem designDesign the client side of an app in which users edit data over an unreliable network. Every edit is saved to local storage on the device as it is made, and the user keeps working…Last asked Sep 2026
- Design watch-next video recommendations and derive the lossesML designDesign the "watch next" list for a large video platform: while someone watches a video, the system picks and orders the videos to offer next. This round goes deep on modeling…Last asked Aug 2026
- 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 Aug 2026
- Design a token-based rate limiter for AI agentsSystem designAI agents call paid services, and each call spends billing tokens. Design a limiter that caps how many tokens each agent or customer can spend over time, enforces the cap across…Last asked Aug 2026
- Design customer support with handoff from virtual agent to humanSystem designUsers chat with a virtual agent and can be escalated to a human support agent. Design the system with the focus on the handoff: how the conversation's context goes with it, who…Last asked Jul 2026
- Design a personalized weekly deals serviceSystem designEvery week each user gets a set of deals picked for them. Design how deals are collected, matched to each user, stored and delivered, and how the weekly run stays on time as users…Last asked Jul 2026
- LLM foundations: architecture, adaptation and steeringML designA broad conversation on large language models: how the architecture works, the ways to adapt a model to a task (full fine-tuning, parameter-efficient methods, prompting), and the…Last asked Jun 2026
- Match tagged problems to skilled programmers at scaleSystem designProblems carry tags and programmers have skills. Design a service that matches each new problem to programmers who are good at its tags, at large scale. Cover the data model, the…Last asked Jun 2026
- Design LeetCodeSystem designUsers solve coding problems in the browser; run their submissions safely against hidden tests, return verdicts quickly, and support live contests with leaderboards.Last asked May 2026
- Design calendar event conflict handlingSystem designIn a calendar service, design how conflicts between events are found and handled: overlapping events for the same person or room, two bookings made at the same moment, and…Last asked Apr 2026
- Design an embeddable streaming chat interfaceAI systemFor a frontend role: design the interface for a chat agent that other products can embed. Cover the component's API, streaming the agent's replies as they are generated, how…Last asked Apr 2026
- Render more than 100 million points on a mapSystem designFor a frontend role: design a web map that shows more than a hundred million data points. Cover what the server sends at each zoom level (tiles, clustering, aggregation), how the…Last asked Apr 2026
- Design an AI agent rollout for a global enterpriseAI systemA forward-deployed engineering design round. A large global company wants to adopt AI agents across its business. Design the agent and how it gets rolled out: which work it takes…Last asked Mar 2026
- Design a chatbot over structured and unstructured company dataAI systemDesign an assistant that answers employees' questions from two kinds of sources: tables in databases and documents. Cover how a question is routed (query generation for tables…Last asked Feb 2026
- Design near-duplicate video detection at scaleSystem designDetect when an uploaded video is a near copy of one already on a very large platform (re-encoded, cropped, trimmed). Cover how videos are fingerprinted or embedded, how candidates…Last asked Jan 2026
- 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.Last asked Dec 2025
- Design a menu update system for a global restaurant chainSystem designHeadquarters controls the menus shown on many kinds of devices in restaurants worldwide. Menus share global items but have local parts per country, and they change for breakfast…Last asked Nov 2025
- Store words for lexicographic range queriesSystem designDesign storage for a set of words that returns every word in a lexicographic range low, high. For the words aa, aaa, ac, f, z, the range a, b gives aa, aaa, ac and ab, b gives ac…Possibly retired
- Diagnose inconsistent data in a distributed databaseSystem designUsers report reading different values for the same record from a replicated database. How do you find the cause? Go through replication lag, read and write consistency settings…Possibly retired
- SLIs, SLOs and SLAs, then a monitoring designSystem designExplain the difference between SLIs, SLOs and SLAs with an example service. Then design its monitoring: which indicators you measure, how you set targets and error budgets, what…Possibly retired
- Design a bandit recommender that learns from feedbackML designAt each interaction the system must show one item out of a few candidates and then sees whether the user responded. Design a recommender that learns from that feedback online: the…Possibly retired
- 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.Possibly retired
- Design a bot detection systemML designSeparate automated traffic from real users on a large website, in real time, while bots adapt to whatever you deploy.
- 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.
- 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.
- Design a news feedSystem designDesign the home feed for a social network with 1B users: posts from people you follow, ranked, fresh within seconds.
- Design a payment systemSystem designAccept card payments for merchants: authorize, capture, settle with card networks, and reconcile, never charging twice or losing money.
- 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.
- Design a Slack-like chat systemSystem designWorkspaces, channels, threads and direct messages with real-time delivery, unread state, search and history, for large companies.
- 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.
- Design an address autofill systemML designAs a user types an address, suggest the full, valid address they mean, ranked by likelihood and personalized by location and history.
- Design an S3-like object storage systemSystem designStore trillions of objects of any size with eleven nines of durability, and serve reads and writes over an HTTP API at high throughput.
- Design DropboxSystem designSync files across a user's devices and shared folders: upload large files reliably, transfer only what changed, and handle conflicting edits.
- 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.
- Design Google NewsSystem designGather articles from thousands of publishers, group stories about the same event, and show each reader a fresh, personalized front page.
- Design InstagramSystem designUsers post photos and videos, follow each other and scroll a feed; design upload, storage, feed generation and serving media worldwide.
- Design SpotifySystem designStream music to hundreds of millions of listeners: catalog, search, playlists, smooth playback over bad networks, and offline downloads.
- Design TinyURLSystem designTurn long URLs into short links and redirect visitors fast, at billions of redirects a day, with optional custom aliases and expiry.
- 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.
- Design YouTubeSystem designUpload videos, transcode them into many formats, and stream them worldwide with adaptive bitrate, along with views, likes and comments.