Know what to build before you build it.
A living reference of how real large systems are built. Look up a term in 30 seconds, compare your options, and study real architectures as buildable blueprints.
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Flip cards to learn 203 tech terms — quick sessions, no signup.
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30 questions, 3 answers each. Score 26+ to pass.
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Guided sequences for common goals.
System design interview
A guided path through the concepts most interviewers probe: from requirements to a scalable architecture.
9 stepsGreenfield backend
Building a new backend service from scratch with sane defaults that won't immediately paint you into a corner.
7 stepsData-heavy service
When reads, writes, or analytics dominate and a single DB won't hold it.
6 stepsRealtime service
Building a live, push-based experience (chat, dashboards, collab).
6 stepsCategories
203 terms across 26 categories.
Web fundamentals
Accessibility (a11y) · CORS · CSS
Programming concepts
Algorithm · Big-O notation · Data structure
Programming languages
Go (Golang) · Node.js · Python
Frontend
Astro · Next.js · Nuxt
Backend
Deno · Django · Express
Mobile
Expo · Flutter · Jetpack Compose
Desktop
Electron · Tauri
DevOps & deployment
Biome · Bun · CI/CD
Networking
Anycast · DNS · HTTP/3 (QUIC)
API design
API gateway · GraphQL · gRPC
Data modeling
CQRS · Event sourcing · Index
Databases
Cassandra · ClickHouse · Database
Caching
Bloom filter · Cache invalidation · Cache-aside
Queues & streaming
Backpressure · Consumer group · Dead-letter queue (DLQ)
Storage & CDN
Block storage · CDN · Erasure coding
Compute & orchestration
Autoscaling · Bulkhead · Container
Consistency & consensus
ACID · CAP theorem · Eventual consistency
Observability
Circuit breaker · Distributed tracing · Logs
Security & auth
Cryptographic hashing · JWT · mTLS
Cost & capacity
Capacity planning · Multi-tenancy
Client & realtime
CRDT · ETag / conditional requests · Long polling
AI & ML
AI agent · Aider · Anthropic (Claude API)
Web3 & blockchain
Blockchain · DeFi (Decentralized Finance) · Ethereum
Cloud platforms
Amazon S3 · AWS (Amazon Web Services) · AWS Lambda
Data science
Jupyter Notebook · pandas
Game development
Case studies
Real architectures as buildable blueprints.
- YouTubeGlobal video upload, processing, and streaming at scale
- NetflixStreaming-first architecture with an online→nearline→offline tiering
- Twitter/X feedFan-out-on-write vs fan-out-on-read for a timeline
- Uber dispatchReal-time matching of riders to nearby drivers
- InstagramPhoto sharing with a feed and sharding by user
Comparisons
Decide between common stack choices.