https://veeresh-bikkaneti.github.io/system-design-and-architecture/ A free system design course — 36 lessons from beginner to master, with interactive quizzes and an AI tutor. en Wed, 30 Sep 2026 22:50:31 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/scaling-web-service/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/scaling-web-service/ The classic journey from one server to millions of users: vertical and horizontal scaling, load balancers, read replicas, CDNs, and sharding — with the napkin math to back it up. Beginner Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/solid-principles/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/solid-principles/ Five principles for code that survives contact with the future: one job per class, extend without rewriting, substitutes that keep their promises, small interfaces, and dependencies that point at abstractions — told through a home kitchen. Beginner Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/mvc-to-react/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/mvc-to-react/ How forty years of UI architecture fits together: the OOP ideas underneath, Smalltalk's Model-View-Controller, its MVP and MVVM descendants, the single-page app, and React's component model — told through a diner. Beginner Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/cap-theorem/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/cap-theorem/ Why a distributed data store can only pick two of consistency, availability, and partition tolerance — and what that trade-off means in practice. Beginner Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/load-balancers/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/load-balancers/ How traffic gets distributed across a fleet of servers, the layers at which it happens, and the algorithms used to pick a target. Beginner Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/nosql-databases/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/nosql-databases/ Why one database shape doesn’t fit every job: the four NoSQL families — key-value, document, wide-column, and graph — what each is good at, and how to choose between them and good old relational. Beginner Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/data-partitioning/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/data-partitioning/ Splitting a dataset across multiple machines so no single node has to hold — or serve — all of it. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/url-shortener/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/url-shortener/ Our first case-study lesson: apply hashing, sharding, caching, and rate limiting to a real interview classic. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/idempotency/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/idempotency/ Networks fail, so we retry — but a retry can double-charge a credit card. How idempotency keys and idempotent operations make retries safe. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/authn-authz/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/authn-authz/ From passwords to JWTs to OAuth2 — how systems verify who you are (authentication) and decide what you are allowed to do (authorization). Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/caching-strategies/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/caching-strategies/ Cache-aside, read-through, write-through, and write-behind: where caches live, how data gets in and out, and how to survive eviction, TTLs, and stampedes. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/cdns/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/cdns/ How CDNs put your content on every continent: edge PoPs, cache hierarchies, TTLs and purging, origin shields, and accelerating dynamic content. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/cloud-native-architecture/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/cloud-native-architecture/ Regions and availability zones, managed services vs self-hosting, Kubernetes essentials, serverless cold starts, the 12-factor rules, and the bill at the end — how to build on someone else's computer without getting burned. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/message-queues/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/message-queues/ Decoupling producers from consumers with queues: delivery guarantees, ordering, backpressure, and how Kafka, RabbitMQ, and SQS differ. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/api-gateways/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/api-gateways/ The front door of your system: routing, authentication, rate limiting, and request shaping — and how gateways differ from plain reverse proxies. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/bff-backend-for-frontend/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/bff-backend-for-frontend/ Why one generic API fails web, mobile, and partners differently — and how a backend-for-frontend per client type fixes payload size, chattiness, and release coupling, plus the sprawl pitfalls to avoid. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/replication-consistency-models/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/replication-consistency-models/ How copies of your data stay in sync (or don’t): synchronous vs. asynchronous replication, leader-based and leaderless designs, quorums, and the consistency models clients actually observe. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/rate-limiting/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/rate-limiting/ Keeping abusive and accidental traffic from ruining everyone’s day: token bucket, leaky bucket, sliding windows, and distributed rate limiting with Redis. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/microservices-vs-monolith/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/microservices-vs-monolith/ The most argued-over trade-off in backend architecture: when splitting services pays off, when a modular monolith wins, and how to avoid the distributed monolith. Intermediate Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/microservices-patterns-pitfalls/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/microservices-patterns-pitfalls/ The loopholes that turn microservices into a distributed monolith: the independent-deployability test, chatty services and latency budgets, the shared-database cardinal sin, temporal coupling — and when to start with a modular monolith instead. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/resilience-patterns/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/resilience-patterns/ How to stop one slow dependency from taking down everything: timeouts, retries with backoff and jitter, circuit breakers, bulkheads, and graceful degradation. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/stream-vs-batch/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/stream-vs-batch/ Event streams vs batch jobs, lambda vs kappa architectures, and how to choose the right one when the data never stops arriving. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/consensus-raft/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/consensus-raft/ How a cluster of unreliable machines agrees on one truth: Raft leader election, log replication, commit rules, and the failure scenarios that keep it honest. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/sharding-strategies/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/sharding-strategies/ Splitting a dataset across machines without regret: key-based, range-based, and directory-based sharding, consistent hashing with virtual nodes, and the true cost of resharding. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/distributed-transactions/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/distributed-transactions/ Atomicity across machines: two-phase commit, why coordinators block, saga patterns with compensating actions, and the outbox pattern for reliable messaging. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/observability/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/observability/ Metrics, logs, and traces that actually answer questions: RED and USE, sampling math, cardinality explosions, and SLIs, SLOs, and error budgets. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/domain-driven-design/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/domain-driven-design/ Model the business the way the business talks: ubiquitous language, bounded contexts, aggregates, and domain events — plus event storming, the transactional outbox, and a peek at event sourcing. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/anti-corruption-layer/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/anti-corruption-layer/ The translation boundary between your clean domain and the messy outside world: adapters and translators in DDD, a normalization layer between your React SPA and legacy APIs, and the strangler-fig migration that retires the legacy for good. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/design-instagram/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/design-instagram/ The capstone case study: upload pipelines, sharded metadata, CDNs, and the fan-out problem behind a feed that serves a billion photos. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/designing-ai-systems/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/designing-ai-systems/ The systems engineering underneath the magic trick: how a request flows from prompt to answer, RAG vs fine-tuning, agent loops, vector databases, the economics of inference (batching, KV-cache, quantization, caching), and why evals replace dashboards. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/agentic-ai-patterns/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/agentic-ai-patterns/ Multi-agent demos feel magical until production: error cascades, retry loops, exploding context bills, and prompt injection smuggled in through tools. The agent loop, orchestration patterns, the failure math, and the guardrails that keep a team of agents honest. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/event-sourcing-cqrs/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/event-sourcing-cqrs/ Stop storing the current state and start storing the history: the append-only event log as source of truth, snapshots and projections for speed, and CQRS to split reads from writes — with the replay math, ordering guarantees, and failure modes that decide whether the pattern earns its keep. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/designing-chat-at-scale/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/designing-chat-at-scale/ The realtime interview classic: persistent connections, per-conversation ordering, delivery receipts, presence, and group fan-out at WhatsApp scale — and what end-to-end encryption takes away from the server. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/graphql-vs-rest/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/graphql-vs-rest/ REST hands every client the same fixed menu; GraphQL lets each client order exactly what fits on its plate. How the two models differ on fetching, caching, versioning, and security — and how to keep a flexible query language from becoming a denial-of-service cannon. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/multi-region-active-active/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/multi-region-active-active/ Your whole region goes dark at 2 a.m. — now what? RPO and RTO with real numbers, active-passive vs active-active, replication lag, write conflicts and how to survive them, DNS failover, data borders, and why you should set fire to your own plans on purpose. Advanced Wed, 30 Sep 2026 22:48:32 GMT https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/zero-trust-security/ https://veeresh-bikkaneti.github.io/system-design-and-architecture/lesson/zero-trust-security/ The castle-and-moat network is dead: why modern systems authenticate and authorize every single request, how workload identity and mutual TLS make it work, and what it costs when the front desk goes down. Advanced Wed, 30 Sep 2026 22:48:32 GMT