Design a payment systemSystem designAccept card payments for merchants: authorize, capture, settle with card networks, and reconcile, never charging twice or losing money.
Last asked Oct 2026
OpenAI technical screen: system design interview
Round 3 of 7 · 34 questions reported
- Length
- 60 min
- Format
- Design discussion, sometimes drawn in Excalidraw; for some roles, on the same day as the coding screen
- They grade
- A practical design with a concrete API and storage schema, and how you handle deep follow-ups
- Heads-up
- Questions are product-shaped (a notification system, a playground for prompts, an online chess site).
Questions OpenAI asks in this round 34
- Design a video generation service on a scarce GPU poolAI systemUsers submit text-to-video requests that each need minutes of GPU time, and the GPU pool is limited and changes size. Design the request flow, scheduling and workers, how users…Last asked Sep 2026
- 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 Sep 2026
- Design a sandboxed cloud IDESystem designGive every user a browser-based editor with a terminal and a private container that runs their code, starts in seconds, isolates untrusted code, and saves their work.Last asked Oct 2026
- Design a distributed power grid control systemSystem designMonitor and control generators, substations and loads across a power grid, reacting to failures and demand changes in seconds, safely, even when parts of the network are cut off.Last asked Sep 2026
- Design an AI chatbot appAI systemBuild a chatbot app on top of a hosted LLM API: conversations, streamed answers, history, and per-user usage limits.Last asked Sep 2026
- 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…Last asked Sep 2026
- 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 Sep 2026
- Design a digital game store like SteamSystem designDesign a digital game distribution platform like Steam. Players use a desktop client to browse a store, buy games, see what they own in a library, and download, install and update…Last asked Sep 2026
- Design a distributed crossword solverSystem designGiven a large crossword grid with about a hundred slots and a dictionary of around a million words, design a service that fills the grid. One machine cannot search the space fast…Last asked Aug 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 Jun 2026
- 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 May 2026
- Design Google CalendarSystem designCreate events, invite people, handle recurring events and time zones, show free/busy, and send reminders, for hundreds of millions of users.Last asked Jan 2026
- 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 Jan 2026
- Design a webhook delivery systemSystem designDeliver event notifications to customers' HTTP endpoints at least once, with retries and backoff, signing, ordering where it matters, and isolation from slow endpoints.Last asked Nov 2025
- 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.Possibly retired
- Design a real-time trivia battle royale with live spectatorsSystem designDesign a trivia battle royale. A room holds dozens to a hundred or more players. Questions go out round by round; after each round, players who answered wrong and the slowest…Last asked Oct 2026
- Design a streaming AI feature for a large audienceAI systemA consumer product wants to add an AI feature whose answers stream to millions of users in real time. Design the path from the client to the model: how responses stream, how…Last asked Aug 2026
- Mine new information from a huge unlabeled image corpusML designYou have a very large corpus of unlabeled images. Design a system that surfaces examples unlike anything already in the training data, and that finds the images containing a given…Last asked May 2026
- Design an agent harness and its evaluation systemAI systemDesign the harness that runs an AI agent (the loop that calls the model, runs its tools and manages its context) together with the system that evaluates it. Cover how the agent…Last asked Apr 2026
- Defend your research direction and an experiment designML designDiscuss your research area: what the state of the art is, the strengths and weaknesses of the main approaches, your own hands-on experience, and where you think the field is…Last asked Apr 2026
- Design a real-time sensor intelligence systemML designDesign a system that takes in sensor data in real time and runs machine learning on it to produce useful signals as the data arrives. Cover ingestion, the models and how they are…Last asked Apr 2026
- Deduplicate files by size then content hashCodingWalk a directory tree and group files with identical content. Compare file sizes first so large files are hashed only when sizes collide, then hash the rest. Be ready to discuss…Last asked Apr 2026
- Design a RAG system over company docsAI systemEmployees should be able to ask questions about internal documents (Drive, Confluence, Slack, GitHub) and get grounded answers with citations.Last asked Mar 2026
- Improve a chatbot's answers to questions it doesn't knowAI systemUsers ask a ChatGPT-style assistant questions it does not know the answer to. Design how the system notices these questions and gives better answers to them: what it does instead…Last asked Dec 2025
- Design ChatGPT streaming with resumable responses and long conversationsAI systemYou have already sketched a ChatGPT-style chat product. Now go deeper on three follow-ups: how replies stream to the browser (SSE or something else, and why), how a reply survives…Last asked Jul 2026
- 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 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.
- Design a GPU scheduling platformAI systemShare a large GPU cluster among research and production teams: queue training and inference jobs, enforce quotas and priorities, place jobs on topology-aware hardware, and preempt…
- 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 an LLM inference serving platformAI systemDesign the system that serves several large models to many customers with low latency and high GPU utilization.
- Design ChatGPTAI systemDesign a consumer chat product backed by a large language model: conversations, streamed replies, history across devices, at 100M weekly users.
- Design YouTubeSystem designUpload videos, transcode them into many formats, and stream them worldwide with adaptive bitrate, along with views, likes and comments.
- Evaluate a new LLM before launchML designYou have a new model checkpoint. Design the evaluation process that decides whether it ships.