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System Design · Practice
Real interview prompts with full model answers — requirements, architecture, data model, failure modes, and the interviewer pushback you should rehearse. Each drill has a phase timer so you can practise against the clock instead of reading passively.
Product-surface prompts that test rendering, data fetching, state, and performance judgement under a clock.
Design a search autocomplete component that suggests results as the user types, fast enough to feel instant and cheap enough to run on every keystroke.
Google Search suggestions · Algolia InstantSearch · Slack quick switcher
Design an infinite-scrolling social feed with mixed media posts, likes and comments, that stays smooth after a user has scrolled through a thousand items.
Twitter/X timeline · Instagram feed · Facebook News Feed
Design the frontend for a realtime chat application with channels, direct messages, typing indicators, read receipts, and reliable delivery across flaky mobile networks.
Slack · WhatsApp Web · Discord
Design the frontend for an e-commerce storefront: a filterable product listing page, product detail, and a cart that survives across devices and sessions.
Amazon product listing · Shopify storefront · Airbnb search results
Design a file upload experience that handles multi-gigabyte files over unreliable connections, survives a page reload, and reports honest progress.
Dropbox uploader · Google Drive upload · YouTube video upload
Design an admin data table over 100,000+ rows with sorting, filtering, column resizing, inline editing, row selection, and CSV export.
Stripe Dashboard payments table · Airtable grid · Salesforce list view
Org-scale prompts where the grade depends on migration paths, ownership, blast radius, and cost — not just the diagram.
Design the frontend for a collaborative rich-text editor where multiple people edit the same document at the same time and see each other's cursors.
Google Docs · Notion · Confluence
Design a video streaming player with adaptive bitrate that plays back long-form content across desktop, mobile web, and living-room browsers.
Netflix · YouTube · Twitch
Design a component library consumed by 50+ product teams across multiple repositories, brands, and framework versions.
Material UI · Shopify Polaris · Atlassian Design System
Design a realtime analytics dashboard with live-updating charts, where a single view may hold dozens of widgets streaming high-frequency data.
Datadog · Grafana · Google Analytics Realtime
Design a Figma-style infinite canvas design tool where users manipulate thousands of vector objects with pan, zoom, and multi-user editing.
Figma · Miro · Excalidraw
Design a cross-channel notification center that delivers in-app, push, and email notifications with a consistent read state across every device a user owns.
GitHub notifications · Slack activity feed · Linear inbox
Design a client-side feature flag and experimentation SDK used by every product team in the company, covering flag evaluation, bucketing, exposure tracking, and safe rollout.
LaunchDarkly · Optimizely · Statsig
Drills go faster once you can size things in your head. Learn the reference numbers first.
Frontend Estimation →