Path System design AI engineering Databases Distributed systems Low level design Articles
Level Foundation Core Senior Staff Design questions only
Patterns Two systems, two lifetimes Claim with an expiry Hot key Fan out on write or on read Admit at the door Cut the map into cells Append now, merge later Safe retries Replicas that vote Precompute the read Number every change Serve from the edge One owner per key Bytes first, pointer last The answer that never came
Topics Scaling6 Estimation3 Reliability20 Load balancing5 Networking13 Caching12 Data modelling11 Replication13 Sharding8 Consistency13 Consensus and coordination4 Transactions and locking9 Concurrency10 Storage and indexes9 SQL9 NoSQL4 Queues and streams14 Real-time10 API design8 Identity and auth10 Security9 Observability7 Architecture and deployment8 Rate limiting and overload5 Search5 Location2 Files and media4 Payments4 Analytics4 Interview craft4 Testing and CI2 Remote work7 India scale3 LLMs8 Retrieval (RAG)10 Agents14 MCP and protocols5 Evals2 Object oriented7 SOLID8 Design patterns17 TypeScript31