Systems Atlas

Master system design from first principles to production.

From foundational mental models to principal-level architectural judgment, for senior, staff, and principal engineers. 326 topics and 32 system dissections, each with mechanisms, capacity math, failure analysis, runnable examples, and interview preparation.

Written and validated so far: 10 of 326 topics, 0 of 32 system dissections. Items without a link are planned and not yet written.

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A. Design method and quantitative reasoning18 items · 10 written ·

Functional and non-functional requirementsFoundational · 1.3 h
Constraints, assumptions, and architecture driversFoundational · 1.3 h
Workload characterization and traffic modelingIntermediate · 1.5 h
LatencyFoundational · 1.3 h
ThroughputFoundational · 1.3 h
P99 latencyIntermediate · 1.5 h
Tail latencyAdvanced · 2 h
Back-of-the-envelope capacity estimationFoundational · 1.3 h
Latency budgets and critical-path analysisIntermediate · 1.5 h
Concurrency, utilization, saturation, and bottlenecksIntermediate · 1.5 h
Storage, bandwidth, memory, and IOPS calculationsNot yet written · Foundational · 1.3 h
Little’s Law and practical queueing theoryNot yet written · Advanced · 2 h
Availability and reliability mathematicsNot yet written · Intermediate · 1.5 h
Failure-budget and risk calculationsNot yet written · Advanced · 2 h
Architecture fitness functionsNot yet written · Advanced · 2 h
Decision criteria and trade-off matricesNot yet written · Intermediate · 1.5 h
Architecture decision recordsNot yet written · Intermediate · 1.5 h
Reversible versus irreversible decisionsNot yet written · Advanced · 2 h

B. Computer systems15 items · 0 written ·

Processes, threads, coroutines, and event loopsNot yet written · Foundational · 1.3 h
Blocking versus non-blocking I/ONot yet written · Foundational · 1.3 h
Async I/O and schedulingNot yet written · Intermediate · 1.5 h
File descriptors, sockets, and resource limitsNot yet written · Intermediate · 1.5 h
System calls and context switchingNot yet written · Intermediate · 1.5 h
CPU caches, locality, false sharing, and NUMANot yet written · Advanced · 2 h
Serialization, compression, and zero-copyNot yet written · Intermediate · 1.5 h
Race conditionsNot yet written · Intermediate · 1.5 h
Thread safetyNot yet written · Intermediate · 1.5 h
DeadlocksNot yet written · Intermediate · 1.5 h
Atomicity, visibility, and memory orderingNot yet written · Advanced · 2 h
Livelock, starvation, and lock-free programmingNot yet written · Advanced · 2 h
Memory leaksNot yet written · Intermediate · 1.5 h
Garbage collectionNot yet written · Intermediate · 1.5 h
CPU, heap, lock-contention, and I/O profilingNot yet written · Advanced · 2 h

C. Networking and web foundations23 items · 0 written ·

TCP versus UDPNot yet written · Foundational · 1.3 h
DNSNot yet written · Foundational · 1.3 h
HTTP semantics, methods, status codes, and headersNot yet written · Foundational · 1.3 h
HTTP caching and conditional requestsNot yet written · Intermediate · 1.5 h
Connection establishment, keep-alive, and drainingNot yet written · Intermediate · 1.5 h
Congestion control and head-of-line blockingNot yet written · Advanced · 2 h
NAT, firewalls, routing, anycast, and BGP fundamentalsNot yet written · Intermediate · 1.5 h
Packet loss, jitter, retransmission, and MTU problemsNot yet written · Advanced · 2 h
TLSNot yet written · Intermediate · 1.5 h
Certificate authorities, PKI, and mutual TLSNot yet written · Advanced · 2 h
HTTP/2 and HTTP/3Not yet written · Intermediate · 1.5 h
Reverse proxiesNot yet written · Foundational · 1.3 h
Forward proxies, tunnels, ingress, and egressNot yet written · Intermediate · 1.5 h
Load balancingNot yet written · Foundational · 1.3 h
L4 versus L7 load balancingNot yet written · Intermediate · 1.5 h
Gateways and routersNot yet written · Intermediate · 1.5 h
CORSNot yet written · Foundational · 1.3 h
WebSocketsNot yet written · Intermediate · 1.5 h
Server-Sent EventsNot yet written · Intermediate · 1.5 h
Long pollingNot yet written · Foundational · 1.3 h
CDNsNot yet written · Foundational · 1.3 h
Edge cachingNot yet written · Intermediate · 1.5 h
Origin shielding and CDN request collapsingNot yet written · Advanced · 2 h

D. API and contract design19 items · 0 written ·

REST resource modelingNot yet written · Foundational · 1.3 h
Pagination: offset, cursor, and keysetNot yet written · Intermediate · 1.5 h
Filtering, sorting, sparse fields, and bulk operationsNot yet written · Intermediate · 1.5 h
API error models and partial successNot yet written · Intermediate · 1.5 h
Idempotency keysNot yet written · Intermediate · 1.5 h
Deadlines and cancellation propagationNot yet written · Intermediate · 1.5 h
Long-running operation APIsNot yet written · Intermediate · 1.5 h
WebhooksNot yet written · Intermediate · 1.5 h
Webhook replay protection and signature verificationNot yet written · Advanced · 2 h
API gatewaysNot yet written · Intermediate · 1.5 h
Backend-for-frontend architectureNot yet written · Intermediate · 1.5 h
GraphQL challengesNot yet written · Intermediate · 1.5 h
GraphQL federation and query-complexity controlsNot yet written · Advanced · 2 h
gRPCNot yet written · Intermediate · 1.5 h
Protocol Buffers compatibilityNot yet written · Advanced · 2 h
API versioningNot yet written · Intermediate · 1.5 h
Semantic versioningNot yet written · Foundational · 1.3 h
Compatibility, deprecation, and sunset policiesNot yet written · Advanced · 2 h
Consumer-driven contract testingNot yet written · Advanced · 2 h

E. Data systems and storage internals34 items · 0 written ·

Relational modeling and normalizationNot yet written · Foundational · 1.3 h
Database indexingNot yet written · Foundational · 1.3 h
Query optimizationNot yet written · Intermediate · 1.5 h
N+1 queriesNot yet written · Foundational · 1.3 h
Connection poolingNot yet written · Intermediate · 1.5 h
Transactions and ACIDNot yet written · Foundational · 1.3 h
Isolation levels and transaction anomaliesNot yet written · Intermediate · 1.5 h
MVCC and serializabilityNot yet written · Advanced · 2 h
Optimistic lockingNot yet written · Intermediate · 1.5 h
Pessimistic concurrency controlNot yet written · Intermediate · 1.5 h
Composite, covering, and secondary indexesNot yet written · Intermediate · 1.5 h
Denormalization and materialized viewsNot yet written · Intermediate · 1.5 h
Access-pattern-driven NoSQL modelingNot yet written · Intermediate · 1.5 h
B-trees and LSM treesNot yet written · Advanced · 2 h
Write-ahead logs, checkpoints, and recoveryNot yet written · Advanced · 2 h
Buffer pools, pages, and storage layoutNot yet written · Advanced · 2 h
Compaction and read/write amplificationNot yet written · Advanced · 2 h
Read replicasNot yet written · Intermediate · 1.5 h
ReplicationNot yet written · Intermediate · 1.5 h
PartitioningNot yet written · Intermediate · 1.5 h
ShardingNot yet written · Advanced · 2 h
Consistent and rendezvous hashingNot yet written · Advanced · 2 h
Hot keys, hot partitions, and rebalancingNot yet written · Advanced · 2 h
Database migrationsNot yet written · Intermediate · 1.5 h
Schema versioningNot yet written · Intermediate · 1.5 h
Online schema changes and large backfillsNot yet written · Advanced · 2 h
Change data captureNot yet written · Advanced · 2 h
Search and inverted indexesNot yet written · Intermediate · 1.5 h
Time-series databasesNot yet written · Advanced · 2 h
Graph databasesNot yet written · Intermediate · 1.5 h
Vector databases and approximate-nearest-neighbor indexesNot yet written · Advanced · 2 h
Columnar and analytical storageNot yet written · Advanced · 2 h
Blob and object storageNot yet written · Intermediate · 1.5 h
Polyglot persistence and data ownershipNot yet written · Principal · 2 h

F. Distributed systems25 items · 0 written ·

Partial failure and failure detectionNot yet written · Intermediate · 1.5 h
Network partitionsNot yet written · Intermediate · 1.5 h
CAP theoremNot yet written · Intermediate · 1.5 h
PACELCNot yet written · Advanced · 2 h
Eventual consistencyNot yet written · Intermediate · 1.5 h
Linearizable, sequential, causal, and eventual consistencyNot yet written · Advanced · 2 h
Read-your-writes and monotonic-read guaranteesNot yet written · Intermediate · 1.5 h
Read/write quorumsNot yet written · Advanced · 2 h
Tunable consistencyNot yet written · Advanced · 2 h
Clock skewNot yet written · Intermediate · 1.5 h
Lamport clocksNot yet written · Advanced · 2 h
Vector clocks and version vectorsNot yet written · Advanced · 2 h
Hybrid logical clocksNot yet written · Advanced · 2 h
CRDTs and conflict resolutionNot yet written · Advanced · 2 h
Gossip, membership, and anti-entropyNot yet written · Advanced · 2 h
Leader electionNot yet written · Advanced · 2 h
Raft and Paxos conceptsNot yet written · Advanced · 2 h
Consensus safety and livenessNot yet written · Principal · 2 h
Leases, fencing tokens, and split brainNot yet written · Advanced · 2 h
Distributed locksNot yet written · Advanced · 2 h
Distributed transactionsNot yet written · Advanced · 2 h
Two-phase commitNot yet written · Advanced · 2 h
Atomic commit and blocking failure modesNot yet written · Principal · 2 h
Exactly-once claims versus end-to-end effectsNot yet written · Advanced · 2 h
Invariant-first distributed-system designNot yet written · Principal · 2 h

G. Messaging, streaming, and workflows22 items · 0 written ·

Message queuesNot yet written · Foundational · 1.3 h
Publish/subscribeNot yet written · Foundational · 1.3 h
Delivery semanticsNot yet written · Intermediate · 1.5 h
Ordering and partition keysNot yet written · Intermediate · 1.5 h
Consumer groups and parallel processingNot yet written · Intermediate · 1.5 h
Acknowledgements and visibility timeoutsNot yet written · Intermediate · 1.5 h
Dead-letter queuesNot yet written · Intermediate · 1.5 h
Poison messages, quarantine, and replayNot yet written · Advanced · 2 h
Event-driven architectureNot yet written · Intermediate · 1.5 h
Transactional outbox and inbox patternsNot yet written · Advanced · 2 h
Dual-write failure and reconciliationNot yet written · Advanced · 2 h
Event schemas and schema registriesNot yet written · Advanced · 2 h
Event notification versus event-carried state transferNot yet written · Advanced · 2 h
Event sourcingNot yet written · Advanced · 2 h
CQRSNot yet written · Advanced · 2 h
Stream-processing windowsNot yet written · Advanced · 2 h
Watermarks and late-arriving eventsNot yet written · Advanced · 2 h
Cron jobsNot yet written · Foundational · 1.3 h
Durable timers and duplicate executionNot yet written · Advanced · 2 h
Saga patternsNot yet written · Advanced · 2 h
Workflow engines and durable executionNot yet written · Advanced · 2 h
Orchestration versus choreographyNot yet written · Advanced · 2 h

H. Performance and resilience30 items · 0 written ·

TimeoutsNot yet written · Foundational · 1.3 h
RetriesNot yet written · Foundational · 1.3 h
Exponential backoffNot yet written · Foundational · 1.3 h
Retry budgetsNot yet written · Advanced · 2 h
Circuit breakersNot yet written · Intermediate · 1.5 h
Bulkheads and isolation poolsNot yet written · Intermediate · 1.5 h
Rate limitingNot yet written · Intermediate · 1.5 h
BackpressureNot yet written · Intermediate · 1.5 h
Load shedding and admission controlNot yet written · Advanced · 2 h
Graceful degradation and brownoutsNot yet written · Advanced · 2 h
Caching strategiesNot yet written · Foundational · 1.3 h
Cache invalidationNot yet written · Intermediate · 1.5 h
Cache stampedes and request coalescingNot yet written · Advanced · 2 h
Cache admission and eviction algorithmsNot yet written · Advanced · 2 h
Probabilistic data structuresNot yet written · Advanced · 2 h
Batching, pipelining, and parallelismNot yet written · Intermediate · 1.5 h
Load, stress, spike, and soak testingNot yet written · Intermediate · 1.5 h
Benchmark design and coordinated omissionNot yet written · Advanced · 2 h
Health checksNot yet written · Foundational · 1.3 h
Graceful shutdown and connection drainingNot yet written · Intermediate · 1.5 h
Horizontal scalingNot yet written · Foundational · 1.3 h
Vertical scalingNot yet written · Foundational · 1.3 h
AutoscalingNot yet written · Intermediate · 1.5 h
Cold startsNot yet written · Intermediate · 1.5 h
Serverless limitsNot yet written · Intermediate · 1.5 h
Blast-radius containmentNot yet written · Advanced · 2 h
Single points of failure and correlated failureNot yet written · Advanced · 2 h
Safe defaults, kill switches, and operational guardrailsNot yet written · Advanced · 2 h
Failure-mode and effects analysisNot yet written · Advanced · 2 h
Chaos engineeringNot yet written · Advanced · 2 h

I. Observability and operations22 items · 0 written ·

LoggingNot yet written · Foundational · 1.3 h
Structured logging and correlation identifiersNot yet written · Intermediate · 1.5 h
MetricsNot yet written · Foundational · 1.3 h
Metric cardinality and histogram designNot yet written · Advanced · 2 h
Distributed tracingNot yet written · Intermediate · 1.5 h
Trace sampling and context propagationNot yet written · Advanced · 2 h
OpenTelemetry and telemetry pipelinesNot yet written · Advanced · 2 h
MonitoringNot yet written · Foundational · 1.3 h
ObservabilityNot yet written · Intermediate · 1.5 h
Golden Signals, RED, and USE methodsNot yet written · Intermediate · 1.5 h
SLAs, SLOs, and SLIsNot yet written · Intermediate · 1.5 h
Error budgetsNot yet written · Intermediate · 1.5 h
AlertsNot yet written · Foundational · 1.3 h
Multi-window burn-rate alertsNot yet written · Advanced · 2 h
Alert fatigue and symptom-based alertingNot yet written · Advanced · 2 h
Production incidentsNot yet written · Foundational · 1.3 h
Incident command and incident communicationNot yet written · Intermediate · 1.5 h
On-call engineeringNot yet written · Intermediate · 1.5 h
Runbook design and operational ownershipNot yet written · Intermediate · 1.5 h
Sustainable on-call rotationsNot yet written · Advanced · 2 h
PostmortemsNot yet written · Intermediate · 1.5 h
Production-readiness reviewsNot yet written · Advanced · 2 h

J. Security, privacy, and multi-tenancy28 items · 0 written ·

Threat modeling and abuse casesNot yet written · Intermediate · 1.5 h
Authentication versus authorizationNot yet written · Foundational · 1.3 h
Identity and access managementNot yet written · Intermediate · 1.5 h
RBAC versus ABACNot yet written · Intermediate · 1.5 h
Least privilege and separation of dutiesNot yet written · Intermediate · 1.5 h
OAuthNot yet written · Intermediate · 1.5 h
OpenID Connect and PKCENot yet written · Advanced · 2 h
JWT rotationNot yet written · Intermediate · 1.5 h
Workload identityNot yet written · Advanced · 2 h
Secrets managementNot yet written · Intermediate · 1.5 h
SQL injectionNot yet written · Foundational · 1.3 h
Cross-site scriptingNot yet written · Foundational · 1.3 h
Cross-site request forgeryNot yet written · Foundational · 1.3 h
Server-side request forgeryNot yet written · Intermediate · 1.5 h
Request smuggling and insecure deserializationNot yet written · Advanced · 2 h
Encryption in transitNot yet written · Foundational · 1.3 h
Encryption at restNot yet written · Intermediate · 1.5 h
Envelope encryptionNot yet written · Advanced · 2 h
KMS, HSMs, and crypto agilityNot yet written · Advanced · 2 h
Web application firewallsNot yet written · Intermediate · 1.5 h
DDoS protectionNot yet written · Intermediate · 1.5 h
Tenant isolation and noisy-neighbor controlsNot yet written · Advanced · 2 h
Supply-chain security, SBOMs, and provenanceNot yet written · Advanced · 2 h
Audit logs and tamper evidenceNot yet written · Advanced · 2 h
Data classification, retention, and deletionNot yet written · Intermediate · 1.5 h
Data residency and sovereigntyNot yet written · Advanced · 2 h
Privacy-by-designNot yet written · Advanced · 2 h
Security incident containmentNot yet written · Advanced · 2 h

K. Platform and delivery engineering27 items · 0 written ·

DockerNot yet written · Foundational · 1.3 h
Container image layers and multi-stage buildsNot yet written · Intermediate · 1.5 h
KubernetesNot yet written · Intermediate · 1.5 h
Helm chartsNot yet written · Intermediate · 1.5 h
Kubernetes controllers and reconciliationNot yet written · Advanced · 2 h
Kubernetes requests, limits, QoS, and disruption budgetsNot yet written · Advanced · 2 h
Liveness and readiness probesNot yet written · Intermediate · 1.5 h
Persistent storage in KubernetesNot yet written · Advanced · 2 h
Service discoveryNot yet written · Intermediate · 1.5 h
Service mesh architecture and trade-offsNot yet written · Advanced · 2 h
CI/CDNot yet written · Foundational · 1.3 h
Build cachingNot yet written · Intermediate · 1.5 h
Reproducible and hermetic buildsNot yet written · Advanced · 2 h
Dependency management and dependency hellNot yet written · Intermediate · 1.5 h
Infrastructure as codeNot yet written · Foundational · 1.3 h
TerraformNot yet written · Intermediate · 1.5 h
GitOpsNot yet written · Advanced · 2 h
Policy as code and admission controlNot yet written · Advanced · 2 h
Artifact promotion and environment parityNot yet written · Intermediate · 1.5 h
Feature flagsNot yet written · Foundational · 1.3 h
Rolling deploymentsNot yet written · Foundational · 1.3 h
Blue-green deploymentsNot yet written · Intermediate · 1.5 h
Canary releasesNot yet written · Intermediate · 1.5 h
Progressive delivery and automated canary analysisNot yet written · Advanced · 2 h
Rollbacks and roll-forwardsNot yet written · Intermediate · 1.5 h
Platform engineering and paved roadsNot yet written · Principal · 2 h
Developer experience as a platform concernNot yet written · Principal · 2 h

L. Multi-region and continuity16 items · 0 written ·

Regions, availability zones, and failure domainsNot yet written · Foundational · 1.3 h
Multi-region deploymentsNot yet written · Advanced · 2 h
Active-passive versus active-active architectureNot yet written · Advanced · 2 h
Regional traffic steeringNot yet written · Advanced · 2 h
Cross-region replication and write ownershipNot yet written · Advanced · 2 h
Failover and failbackNot yet written · Advanced · 2 h
RTO and RPONot yet written · Intermediate · 1.5 h
Business-impact analysisNot yet written · Intermediate · 1.5 h
Backups and restorationNot yet written · Foundational · 1.3 h
Immutable backups and cyber recoveryNot yet written · Advanced · 2 h
Restore verificationNot yet written · Intermediate · 1.5 h
Disaster recoveryNot yet written · Advanced · 2 h
Regional evacuation and capacity reservationNot yet written · Advanced · 2 h
Control-plane versus data-plane survivabilityNot yet written · Principal · 2 h
Cell-based architectureNot yet written · Principal · 2 h
Disaster-recovery exercisesNot yet written · Advanced · 2 h

M. Architecture and evolution15 items · 0 written ·

Cohesion, coupling, modularity, and information hidingNot yet written · Foundational · 1.3 h
Modular monolithsNot yet written · Intermediate · 1.5 h
Microservice boundaries and service sizingNot yet written · Advanced · 2 h
Hexagonal and ports-and-adapters architectureNot yet written · Intermediate · 1.5 h
Domain-driven design and bounded contextsNot yet written · Advanced · 2 h
Synchronous versus asynchronous compositionNot yet written · Advanced · 2 h
Strangler migrationsNot yet written · Advanced · 2 h
Branch by abstractionNot yet written · Intermediate · 1.5 h
Dual reads, dual writes, and migration reconciliationNot yet written · Advanced · 2 h
Anti-corruption layersNot yet written · Intermediate · 1.5 h
Multi-tenancy architecture modelsNot yet written · Advanced · 2 h
Control-plane and data-plane separationNot yet written · Advanced · 2 h
Evolutionary architectureNot yet written · Principal · 2 h
Technical-debt portfolio managementNot yet written · Principal · 2 h
Build versus buy versus managed servicesNot yet written · Principal · 2 h

N. Testing and correctness15 items · 0 written ·

Test portfolios and confidence boundariesNot yet written · Intermediate · 1.5 h
Unit, integration, component, and end-to-end testingNot yet written · Foundational · 1.3 h
Contract and compatibility testingNot yet written · Intermediate · 1.5 h
Property-based testingNot yet written · Intermediate · 1.5 h
Fuzz testingNot yet written · Intermediate · 1.5 h
Invariant testingNot yet written · Advanced · 2 h
Deterministic distributed-system simulationNot yet written · Principal · 2 h
Concurrency and race testingNot yet written · Advanced · 2 h
Fault-injection testingNot yet written · Advanced · 2 h
Shadow traffic and traffic replayNot yet written · Advanced · 2 h
Differential testingNot yet written · Advanced · 2 h
Migration and rollback testingNot yet written · Advanced · 2 h
Restore and disaster-recovery testingNot yet written · Advanced · 2 h
Formal methods and model checkingNot yet written · Principal · 2 h
Production verificationNot yet written · Advanced · 2 h

O. Economics and principal-level leadership17 items · 0 written ·

Cloud unit economicsNot yet written · Intermediate · 1.5 h
Cost per request, tenant, and workloadNot yet written · Intermediate · 1.5 h
Cost optimizationNot yet written · Intermediate · 1.5 h
Total cost of ownershipNot yet written · Advanced · 2 h
Operational burden and opportunity costNot yet written · Principal · 2 h
Capacity commitments and elasticityNot yet written · Advanced · 2 h
Architecture narratives and review documentsNot yet written · Principal · 2 h
Executive communicationNot yet written · Principal · 2 h
Cross-team contracts and ownership boundariesNot yet written · Principal · 2 h
Dependency governanceNot yet written · Principal · 2 h
Technical strategy and sequencingNot yet written · Principal · 2 h
Migration economicsNot yet written · Principal · 2 h
Standardization versus autonomyNot yet written · Principal · 2 h
Risk management and compliance evidenceNot yet written · Principal · 2 h
Decision facilitation, dissent, and escalationNot yet written · Principal · 2 h
Mentoring architecture reasoningNot yet written · Principal · 2 h
Measuring architecture outcomesNot yet written · Principal · 2 h

Systems dissected32 items · 0 written ·

URL shortener / BitlyNot yet written · Principal · 4 h
Cloud file storage / DropboxNot yet written · Principal · 4 h
Local delivery serviceNot yet written · Principal · 4 h
Ticket booking / TicketmasterNot yet written · Principal · 4 h
Social news feedNot yet written · Principal · 4 h
Dating and matching service / TinderNot yet written · Principal · 4 h
Online judge / LeetCodeNot yet written · Principal · 4 h
Messaging platform / WhatsAppNot yet written · Principal · 4 h
Distributed rate limiterNot yet written · Principal · 4 h
Video platform / YouTubeNot yet written · Principal · 4 h
Live commentsNot yet written · Principal · 4 h
Top-K video analyticsNot yet written · Principal · 4 h
Ride-sharing platform / UberNot yet written · Principal · 4 h
Distributed web crawlerNot yet written · Principal · 4 h
Advertisement click aggregatorNot yet written · Principal · 4 h
Social-post searchNot yet written · Principal · 4 h
Local business discovery / YelpNot yet written · Principal · 4 h
Photo-sharing platform / InstagramNot yet written · Principal · 4 h
Fitness activity platform / StravaNot yet written · Principal · 4 h
Distributed cacheNot yet written · Principal · 4 h
Online auctionNot yet written · Principal · 4 h
Distributed job schedulerNot yet written · Principal · 4 h
News aggregatorNot yet written · Principal · 4 h
Price-tracking serviceNot yet written · Principal · 4 h
Notification systemNot yet written · Principal · 4 h
Retail brokerage platform / RobinhoodNot yet written · Principal · 4 h
Collaborative document editor / Google DocsNot yet written · Principal · 4 h
Payment systemNot yet written · Principal · 4 h
Metrics-monitoring platformNot yet written · Principal · 4 h
Online chess platformNot yet written · Principal · 4 h
LLM conversational platform / ChatGPTNot yet written · Principal · 4 h
Flash-sale platformNot yet written · Principal · 4 h

Cross-cutting patterns (not yet written) · All system dissections · Traceability matrix