FoundationsLive
RPC Deadlines
Carry one shrinking time budget through the whole call graph.
Open refresher →The 2026 field guide for systems engineersSee the system.
See the system.
Reason through failure.
Forty-one concise concepts, complete architectures, incident scenarios, and current industry research—organized for the decisions engineers make in production.
41 concepts12 system designs8 incident drills
Clientsrequest
→Load balancerroute
→Servicescompute
↓
Databasedurable state
Cachefast reads
Queueasync work
Start with the decisions that matter
Featured topics
Each visual one-pager moves from intuition to mechanics, trade-offs, failure scenarios, and real-world implications.
ConsensusLive
Leases & Fencing
Keep a paused former owner from corrupting shared state.
Open refresher →TransactionsLive
Transactional Outbox
Commit business state and publish intent without a dual-write gap.
Open refresher →StorageLive
Distributed Caching
Design freshness, invalidation, and cold-cache recovery explicitly.
Open refresher →MessagingLive
Schema Evolution
Change event contracts while old code and historical replay coexist.
Open refresher →ArchitectureLive
Cell Architecture
Scale through repeatable slices with bounded tenant blast radius.
Open refresher →Choose your depth
Learning paths
The same concepts, organized around what you need to do next.
01
Foundations
Refresh the primitives: failure, time, consistency, replication, and scale.
Start the path →02Interview Prep
Practice the follow-up questions that distinguish senior-level reasoning.
Practice questions →03Architect Path
Connect technical choices to invariants, risk, cost, and operations.
Explore architecture →04Manager Path
Review designs through failure impact, ownership, and decision quality.
Open manager mode →Architecture library
Explore system designs →Twelve complete system design walkthroughs.
Trace requests, examine architecture decisions, pressure-test failures, and connect each design back to its core concepts.