System Design - scalability
#01 Distributed Systems

Build an AI Agent Task Queue with Resumability Premium

Design an agent execution framework that handles long-running tool calls, persists agent state so tasks can be paused and resumed across server restarts, enforces token and cost caps, and supports parallel sub-agent execution.

Read
#02 Data Engineering

Build Amazon's Product Search Ranking Premium

Design a search ranking system that incorporates real-time inventory, pricing, and sales velocity signals into results, personalizes rankings per user, and re-indexes a product catalog of 500 million items.

Read
#03 Data Engineering

Build Amazon's Review Aggregation Pipeline Premium

Design a review processing pipeline that deduplicates submissions, filters fraudulent reviews using behavioral signals, computes rolling star averages, and surfaces the most helpful reviews per product.

Read
#04 Distributed Systems

Build a Concurrent Device Session Manager Premium

Design a session enforcement system that limits streaming to N concurrent devices per subscription plan, kicks the oldest session when the limit is exceeded, and works correctly across distributed servers.

Read
#05 Distributed Systems

Build a Distributed Cron Job Scheduler Premium

Design a cron scheduler that guarantees exactly-once execution of jobs across a cluster of nodes, handles missed executions during downtime, and scales to millions of scheduled tasks.

Read
#06 Distributed Systems

Build a Distributed Lock Manager and Leader Election Service Premium

Design a distributed coordination service that provides mutual exclusion across a cluster, implements lease-based locks that expire on node failure, and enables leader election for singleton workloads.

Read
#07 Distributed Systems

Build a Distributed Rate Limiter Across 100+ API Gateway Nodes Premium

Design a rate limiter that enforces per-user and per-tenant request limits globally across a horizontally scaled API gateway fleet, with no single coordinator bottleneck and sub-milliseclient enforcement latency.

Read
#08 Distributed Systems

Build a Distributed Shopping Cart with Guest Session Merge Premium

Design a shopping cart system that persists items for guest users, merges the guest cart into the authenticated cart on sign-in, handles concurrent modifications, and survives server restarts.

Read
#09 Distributed Systems

Build a Distributed Unique ID Generator Free

Design a system that generates globally unique, roughly time-sortable IDs across thousands of nodes with no coordination overhead and zero collisions under any failure scenario.

Read
#10 Scalability

Build Facebook Live Low-Latency Video Streaming Premium

Design a live video streaming infrastructure that ingests a broadcaster's stream, encodes it into multiple bitrates in real-time, and delivers it to millions of concurrent viewers with under 5 seconds of latency.

Read