System Design — High Level Design
A structured path through the system design interview — from foundational building blocks to distributed systems, staff-level platforms, and modern AI systems. Every question is a full 25-section deep dive: requirements, capacity math, an interactive architecture diagram, deep dives, tradeoffs, and interview tips.
62
Questions
30
Available now
5
Learning tiers
12+
Companies
Foundations
Building-block systems every senior engineer must be able to design cold — caches, rate limiters, gateways, and stores.
URL Shortener
Design a TinyURL-style service that maps billions of long URLs to short, unique, low-latency redirects.
Rate Limiter
Design a distributed rate limiter that throttles requests per client with predictable latency and accuracy.
Distributed Cache
Design a horizontally-scalable cache like Redis/Memcached with sharding, eviction, and high hit rates.
Key-Value Store
Design a Dynamo-style distributed key-value store with tunable consistency and fault tolerance.
Logging System
Design a high-throughput, searchable logging pipeline that ingests terabytes of logs per day.
Metrics Collection
Design a time-series metrics system that collects, aggregates, and stores millions of data points per second.
Monitoring System
Design an end-to-end monitoring and alerting platform with dashboards, thresholds, and on-call routing.
API Gateway
Design an API gateway handling routing, auth, rate limiting, and observability for hundreds of services.
Notification Service
Design a multi-channel (push, SMS, email) notification service delivering billions of messages reliably.
Pastebin
Design a Pastebin-style service for storing and sharing text snippets with expiry and access control.
Common Interview Questions
The product-scale designs asked most often at top companies — feeds, chat, storage, streaming, and marketplaces.
Design a Twitter-scale microblogging platform: tweets, timelines, fan-out, and trending topics.
Design a photo-sharing social network with feeds, stories, media storage, and social graph.
Facebook Feed
Design a news feed with ranking, fan-out, and real-time updates for billions of users.
LinkedIn Feed
Design a professional-network feed with relevance ranking, connections, and activity fan-out.
Design a community platform with subreddits, nested comments, voting, and hot/ranking algorithms.
TikTok
Design a short-video platform with a recommendation feed, upload pipeline, and global CDN delivery.
Design a real-time messaging system with delivery receipts, group chat, and end-to-end encryption.
Slack
Design a team-messaging platform with channels, threads, presence, search, and integrations.
Discord
Design a chat + voice platform with servers, channels, low-latency voice, and presence at scale.
Dropbox
Design a file-sync and storage service with chunking, deduplication, and conflict resolution.
Google Drive
Design a collaborative cloud-storage platform with sharing, versioning, and real-time collaboration.
YouTube
Design a video-sharing platform: upload/transcoding pipeline, storage, CDN, and view counting.
Netflix
Design a video-streaming platform with adaptive bitrate, global CDN, and personalized recommendations.
Uber
Design a ride-hailing system with real-time matching, geospatial indexing, and surge pricing.
Amazon
Design an e-commerce platform with catalog, cart, inventory, and order fulfillment at scale.
Payment Gateway
Design a payment gateway with idempotent charges, ledgers, reconciliation, and PCI compliance.
Shopping Cart
Design a shopping-cart service with session persistence, inventory holds, and checkout consistency.
Google Calendar
Design a calendar system with events, recurrence, invitations, reminders, and timezone handling.
Autocomplete
Design a typeahead/autocomplete system with tries, ranking, and sub-50ms suggestions at scale.
Google Search
Design a web-search engine: crawling, inverted index, ranking, and low-latency query serving.
Advanced Distributed Systems
The distributed-systems primitives behind everything else — queues, locks, consensus, and multi-region data.
Kafka
Design a distributed event-streaming log with partitions, replication, and consumer groups.
RabbitMQ
Design a message broker with exchanges, queues, routing, acknowledgements, and delivery guarantees.
Distributed Queue
Design an SQS-style distributed queue with at-least-once delivery, visibility timeouts, and DLQs.
Distributed Lock
Design a distributed lock with fencing tokens, TTLs, and safe failover using Redis or ZooKeeper.
Service Discovery
Design a service-discovery system with health checks, registration, and client-side load balancing.
Feature Flag Platform
Design a feature-flag platform with targeting rules, gradual rollouts, and low-latency evaluation.
Configuration Service
Design a dynamic configuration service with versioning, propagation, and safe rollbacks.
Leader Election
Design a leader-election mechanism using consensus, leases, and automatic failover.
Consensus
Design a consensus system (Raft/Paxos) providing a replicated, linearizable state machine.
Multi-Region Database
Design a globally-distributed database with multi-region replication and conflict resolution.
Service Mesh
Design a service mesh with sidecar proxies, mTLS, traffic shaping, and observability.
Distributed Transaction
Design distributed transactions with sagas, two-phase commit, and eventual consistency tradeoffs.
Staff / Principal
Platform- and org-scale systems: control planes, schedulers, global routing, and multi-tenant SaaS.
CI/CD
Design a CI/CD platform with build pipelines, artifact storage, and safe progressive deployments.
Terraform Cloud
Design an infrastructure-as-code control plane with state management, locking, and plan/apply runs.
GitHub
Design a code-hosting platform with Git storage, pull requests, CI hooks, and search.
Jira
Design an issue-tracking platform with flexible workflows, permissions, and cross-project search.
Cloud Monitoring
Design a cloud-scale monitoring platform ingesting metrics, logs, and traces with alerting.
Cloud Storage
Design an S3-style object store with durability, erasure coding, and multi-region replication.
Azure Resource Manager
Design a cloud resource-management control plane with declarative templates and reconciliation.
Kubernetes Scheduler
Design a container scheduler with bin-packing, constraints, priorities, and preemption.
Control Plane
Design a generic control plane with declarative desired state, reconciliation loops, and drift detection.
Event Bus
Design an org-wide event bus with schema registry, routing, replay, and exactly-once semantics.
Global Load Balancer
Design a global load balancer with geo-DNS, anycast, health-aware routing, and failover.
Multi-Tenant SaaS
Design a multi-tenant SaaS platform with isolation, per-tenant scaling, and noisy-neighbor control.
AI System Design
Designing the systems behind modern AI products — inference serving, retrieval, embeddings, and agents.
Now part of Generative AI
AI system design — ChatGPT, RAG, vector databases, agents, and inference serving — now lives in the dedicated Generative AI hub, alongside foundations, production AI, interview prep, and projects.