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Course

System Design — the skill AI can't replace

AI writes code; engineers decide how systems fit together. Learn the building blocks, walk through real designs the way a strong candidate answers them, and drill the questions interviewers at Indian product companies and FAANG actually ask — SDE-1 to Staff.

Lessons

51

Design walkthroughs

120

Interview questions

397

Module 1

How to answer

The step-by-step way to run a system design interview, and what interviewers at each level look for.

0/10
  1. 1What interviewers evaluate (SDE-1 to Staff)
  2. 2How to approach a design interview
  3. 3Clarifying requirements and scope
  4. 4Back-of-the-envelope estimation
  5. 5Designing the API
  6. 6Data modelling and choosing a database
  7. 7Drawing the high-level design
  8. 8Driving deep dives and trade-offs
  9. 9What impresses interviewers (and red flags)
  10. 10Indian product companies vs FAANG: what changes

Module 2

Scaling fundamentals

How systems grow from one server to millions of users without falling over.

0/6
  1. 1Scalability basics
  2. 2Caching
  3. 3Consistent hashing
  4. 4Stateless services and sessions
  5. 5Autoscaling and capacity planning
  6. 6Concurrency, backpressure and load shedding

Module 3

Data at scale

Choosing, replicating, partitioning and querying data when one database is no longer enough.

0/10
  1. 1Databases, replication & sharding
  2. 2SQL vs NoSQL: choosing the store
  3. 3CAP & consistency
  4. 4Consistency models and quorums
  5. 5Distributed transactions: 2PC and sagas
  6. 6Search: inverted indexes and Elasticsearch
  7. 7Object storage and media pipelines
  8. 8Analytics: OLTP vs OLAP and time-series stores
  9. 9Geospatial indexing: geohash, quadtrees and H3
  10. 10Hot keys, hot partitions and fan-out

Module 4

Messaging & events

Queues, streams and workflows: doing work later, reliably, exactly the right number of times.

0/7
  1. 1Message queues & async processing
  2. 2Kafka: partitions, consumer groups and ordering
  3. 3Delivery guarantees and effectively-once
  4. 4Transactional outbox and change data capture
  5. 5Event sourcing and CQRS
  6. 6Durable workflows and job scheduling
  7. 7Webhooks: sending and receiving reliably

Module 5

Reliability, security & operations

Keeping systems up, secure and observable when parts of them fail every day.

0/8
  1. 1Rate limiting
  2. 2Timeouts, retries and circuit breakers
  3. 3Availability, SLOs and error budgets
  4. 4Observability: logs, metrics and traces
  5. 5Multi-region and disaster recovery
  6. 6Consensus and leader election
  7. 7Auth, permissions and multi-tenancy
  8. 8Real-time at scale: WebSockets, SSE and presence

Module 6

AI-era system design

Designing products that call LLMs: slow, costly, non-deterministic dependencies done right.

0/10
  1. 1What changes when an LLM is in the system
  2. 2The AI gateway: routing, failover and budgets
  3. 3Exact, semantic and prompt caching
  4. 4RAG: chunking, embeddings and hybrid retrieval
  5. 5Vector databases and ANN indexes
  6. 6Streaming LLM responses at scale
  7. 7Agents and tool calling: safety and least privilege
  8. 8LLM tracing, evaluation and quality
  9. 9LLM cost engineering
  10. 10Queues and workflows for slow AI steps