Build a Push Notification Routing System Premium
Design a notification dispatch system that routes messages across APNs, FCM, and Web Push, guarantees at-least-once delivery with deduplication, and handles delivery failures with smart retry strategies.
Build a QR Code Generation and Analytics Service Free
Design a system that generates dynamic QR codes at scale, tracks every scan with device and location metadata, and lets users update the destination URL without regenerating the QR code.
Build a RAG Pipeline for an Enterprise Knowledge Base Premium
Design a Retrieval-Augmented Generation pipeline that ingests internal documents, chunks and embeds them, retrieves the most relevant context for each query, and re-ranks results before passing them to the LLM.
Build a Real-Time Analytics Dashboard at 100B Events Premium
Design a product analytics system that ingests billions of events per day, supports sub-second aggregate queries over arbitrary time windows, and powers live dashboards without precomputing every possible metric.
Build a Real-Time Fraud Detection Engine Premium
Design a fraud detection system that evaluates every payment transaction in under 100ms using behavioral, velocity, and network signals, updates risk models continuously, and minimizes false positives that block legitimate users.
Build a Self-Healing Service Mesh Premium
Design a service mesh that continuously monitors the health of every service instance, automatically reroutes traffic away from degraded nodes, and triggers remediation actions without human intervention.
Build a Semantic Search Engine with Hybrid Ranking Premium
Design a search engine that combines keyword-based BM25 scoring with dense vector similarity to handle queries where exact keyword matches are absent but semantic intent is clear.
Build a Shadow Traffic / Dark Launch System Premium
Design a traffic mirroring system that duplicates live production requests to a canary service in real-time, compares responses for divergence, and generates a confidence report without any user-visible impact.
Build Slack's Channel Message Fan-Out and Unread Counts Premium
Design a messaging system that delivers channel messages to thousands of members in a large workspace, maintains accurate unread counts per user per channel, and syncs read state across multiple devices.
Build a Social Graph Service at 500M Users Free
Design a graph service that answers 'does user A follow user B?' in under 1ms, supports mutual friend queries, and stays consistent as billions of follow/unfollow events happen every day.