Audience Gate: Recommended for engineers with ~3+ years of backend, distributed systems, or SRE experience. Designed as an operational reference, architectural blueprint, and deep theoretical curriculum.
- Learning Path & Study Rules — Spaced retention mix, tier gates (Foundation → Staff → Principal), and study protocol.
- Module Contract V2 — Technical depth standards and teaching structure required across all modules.
- Quality Rubric — Grading criteria for incident diagnosis, tradeoff analysis, and capacity math.
- Roadmap Completion Tracker — Progress tracking across all 16 weeks.
- TCP vs UDP — Sequence numbers, flow control, TIME_WAIT exhaustion, sysctl tuning.
- HTTP/1.1 vs HTTP/2 vs HTTP/3 — Multiplexing, HOL blocking, QUIC transport, connection migration.
- DNS Resolution — Recursion, TTL caching, Anycast routing, GEO-DNS, EDNS client subnet.
- CDN Fundamentals — Edge caching, origin shield, cache invalidation, cache stampede mitigation.
- REST vs GraphQL vs gRPC — Protocol buffers, schema governance, N+1 query problem, HTTP/2 streaming.
- WebSockets — Upgrade handshake, stateful connection scaling, ping/pong frames, edge proxies.
- Cloud-Native Networking: Envoy, eBPF & Overlay Networks — xDS control plane, mTLS CPU tax, Cilium eBPF kernel bypass, VXLAN MTU overhead.
- SQL Deep Dive — B-Trees vs LSM-Trees, MVCC, isolation levels (Read Committed to Serializable), EXPLAIN ANALYZE.
- Hardware Bounds: NVMe, PCIe, NUMA & Cache Contention — Flash IOPS saturation, PCIe 4.0/5.0 lane math, NUMA bus contention, L1-L3 cache bouncing.
- CAP Theorem & PACELC — Proof mechanics, linearizability, PACELC latency/consistency tradeoffs under health vs partition.
- Consistency Models — Strict, Linearizable, Sequential, Causal, Eventual consistency bounds.
- Consistent Hashing — Ring topology, virtual nodes, bounded loads, partition rebalancing algorithms.
- Formal Verification: TLA+, Jepsen & DST — TLA+ safety/liveness specifications, Jepsen fault injection, Deterministic Simulation Testing (DST).
- Replication Strategies — Single-leader, multi-leader, leaderless (Dynamo-style), replication lag, split-brain.
- Sharding — Key-based, range-based, directory-based sharding, hot key mitigation, resharding strategies.
- Consensus Raft — Leader election, log replication, joint consensus configuration changes, safety invariants.
- Cassandra Architecture — Memtables, SSTables, Bloom filters, compaction strategies, hint handoff.
- Database Scaling Patterns — Read replicas, connection pooling (PgBouncer), CQRS, materialized views.
- Event-Driven Architecture — Event notification, event-carried state transfer, event sourcing.
- Message Queues and Kafka — Partition logs, consumer groups, offset management, exactly-once semantics.
- Microservices Patterns — Service boundary decomposition, API gateway, BFF pattern.
- Outbox Pattern and CDC — Transactional outbox, Debezium CDC, WAL tailing.
- Saga Pattern — Orchestration vs Choreography, compensation state machines, forward recovery.
- Resilience: Circuit Breakers, Bulkheads, Timeouts, Retries — Cascading failure mitigation, exponential backoff, jitter, load shedding.
- Load Balancing Deep Dive — L4 vs L7 balancing, Maglev, ECMP, health checks, connection draining.
- Rate Limiting Algorithms — Token bucket, leaky bucket, sliding window counter, distributed Redis limiters.
- Search Systems and Inverted Indexes — Lucene index structure, TF-IDF / BM25, postings list compression, Elias-Fano & WAND pruning.
- Vector Databases — HNSW graphs, IVF-PQ product quantization, SIMD AVX-512 distance math, semantic search architectures.
- Unique ID Generation — Snowflake IDs, UUID v4/v7, ticket servers, monotonic clock dependencies.
- Feature Flags and Progressive Delivery — Context evaluation, dark launches, canary rollouts, kill switches.
- Clocks, Time and Ordering — Physical vs Logical time, NTP drift, TrueTime (Google Spanner), bounded uncertainty.
- Lamport Clocks, Vector Clocks & Causality — Causal ordering, partial order graphs, vector clock size bloat.
- CRDTs and Conflict Resolution — State-based (CvRDT) vs Operation-based (CmRDT), LWW-Element-Set, PN-Counters.
- Geospatial Systems — Geohash, S2 geometry, Quadtrees, spatial indexing, k-NN queries.
- Observability — Metrics (Prometheus), Distributed Tracing (OpenTelemetry), Structured Logging, trace context propagation.
- eBPF Observability & Continuous Profiling — Off-CPU latency profiling, kernel tracepoints, continuous flame graphs, Parca/Pyroscope architecture.
- SLOs, SLIs, Error Budgets & Alerting — Multi-window multi-burn-rate alerts, SLA math, error budget policy.
- AuthN, AuthZ, OAuth, mTLS & Secrets — JWT validation, RBAC/ABAC (SpiceDB/OPA), OAuth2 PKCE, secrets rotation.
- Cost, Capacity & FinOps — Unit economics, egress cost optimization, reserved instance sizing, storage tiering.
- Multi-Tenancy Isolation & Noisy Neighbor — Pool vs Silo architecture, fair queuing, tenant quota enforcement.
- Migration and Cutover — Dual-writing, shadow traffic, backfill pipelines, rollback safety checks.
- Testing Distributed Systems — Chaos engineering, fault injection, shadow testing, synthetic monitoring.
- Abuse, Bots & Fraud Defense — CAPTCHA challenges, IP reputation scoring, device fingerprinting, velocity tracking.
- Client Offline & Edge Resilience — Offline-first local storage, optimistic UI updates, background sync queue.
- Week 09: Twitter Feed & WhatsApp — Fan-out on write vs read, timeline caching, WebSocket gateway, end-to-end encryption.
- Week 10: YouTube & Uber — Chunked video transcoding, CDN origin shield, Quadtree location indexing, driver matching.
- Week 11: Payment System & E-Commerce — Double-entry accounting ledger, Stripe-grade idempotency keys, PCI SAQ A scope, checkout saga.
- Week 12: Search Engine & Web Crawler — Distributed crawler frontier, robots.txt parser, PageRank calculation, inverted index sharding.
- Week 13: Distributed KV Store, Kafka & Config Store — Dynamo-style LSM KV store, partition log broker, etcd linearizable config watch.
- Week 14: Collaborative Docs, LLM Serving & Feature Store — OT/CRDT real-time text edit, vLLM PagedAttention GPU inference, offline/online ML feature store.
- Week 15: Mock Interviews — Timed interview prompts, scoring rubric, and feedback checklists.
- Week 16: Final Mastery & Checklists — Architecture review checklist, production readiness checklist, and capstone incident scenario.
- For Incident Response & On-Call: Jump directly to the relevant Wrong Mental Models and Production Failure Patterns sections in each topic file.
- For System Design Preparation: Review the functional/non-functional requirements, capacity math, state diagrams, and DB schema designs in Weeks 09 through 14.
- For Architectural Design Reviews: Consult the checklists in Week 16 alongside the resilience and hardware bounds modules.