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2667 questions of the kind that actually get asked — in interviews, in architecture review boards, and by the person who has to run the thing at 3 AM. Every answer states the trade-off rather than the slogan, and says when the obvious choice is the wrong one.

All areas2667 Architecture Fundamentals81 Distributed Systems101 Data Architecture90 Cloud Architecture87 Networking86 API & Integration Architecture78 Reliability & Resilience88 Observability81 Performance & Capacity Engineering90 Security Architecture95 Cost Architecture & FinOps92 Business Architecture93 Architecture Communication91 Enterprise Architecture91 Legacy Modernization92 AI-Era Architecture86 Software Architecture & Engineering84 Architecture Patterns84 Architecture Decision-Making91 The Architect's Meta-Skills92 Delivery & Release Engineering93 Platform Engineering & Developer Experience92 Testing & Quality Architecture90 Data Platform Architecture88 Streaming & Real-Time Data93 Data Governance & Semantics81 Frontend & Experience Architecture91 Edge, Mobile & IoT88 Regulatory & Data Protection Architecture90 Assurance, Audit & Model Risk88
Difficulty Any beginner intermediate advanced

101 questions in Distributed Systems.

  1. Distributed Systems advanced

    A downstream service slows from 50 ms to 3 s. Within two minutes every service in the request path is down, including ones that do not call it. Explain the mechanism and how you would have prevented it.

    2 min answer cascading-failureretriestimeoutsresilience
  2. Distributed Systems advanced

    A payments platform sees a 20x increase in transaction attempts during a major commerce event. Idempotency, rate limiting, queueing, fraud checks, database contention and a downstream provider all interact. What is the correct ordering of these controls on the request path, and why does ordering matter more than any single control?

    2 min answer razorpaypaymentssurgeidempotency
  3. Distributed Systems intermediate

    An order service must notify inventory, billing, shipping and analytics when an order is placed. Synchronous calls or events? Justify your choice per consumer.

    2 min answer event-drivencouplingavailabilityintegration
  4. Distributed Systems intermediate

    Design an order submission API that is safe when the client cannot tell whether its request succeeded. What exactly do you store, and when?

    2 min answer idempotencyapi-designretries
  5. Distributed Systems advanced

    Design the connection layer for a chat platform holding tens of millions of concurrent WebSocket connections, where users belong to communities ranging from three people to a million. What are the main architectural decisions, and which one causes the most incidents?

    2 min answer websocketsgatewayshardingpresence
  6. Distributed Systems advanced

    Design the system that matches a rider request to a nearby driver. What are the hard parts?

    2 min answer uberdesignmatchinginterview
  7. Distributed Systems advanced

    DynamoDB has evolved through adaptive capacity, on-demand mode and global tables. Which failure mode did each address, and what does the sequence teach about designing partitioned systems?

    2 min answer awsdynamodbpartitioninghot-key
  8. Distributed Systems advanced

    Showing which users are currently online seems trivial and is one of the most expensive features in a chat product. Explain.

    2 min answer slackpresencefanoutcost
  9. Distributed Systems intermediate Multiple choice

    You move a user profile service to eventual consistency and support tickets start arriving: users update their name and the old one is still shown. Fix it without abandoning the architecture.

    2 min answer consistencyreplicationuxread-your-writes
  10. Distributed Transactions advanced

    A stay booking spans payment authorisation, calendar reservation, host notification and a guest confirmation email. A distributed ACID transaction is not available. How do you order the steps and what do you do when a compensation fails?

    3 min answer sagacompensationairbnbbooking
  11. Distributed Transactions advanced

    A workflow succeeds in one service, then the next service crashes before recording the event. How do transactional outbox, durable queues, retries, idempotent consumers and reconciliation each contribute, and which of them is not optional?

    2 min answer temporaloutboxdurable-executionexactly-once
  12. Distributed Transactions advanced Multiple choice

    An order at extreme e-commerce scale must reserve inventory, charge payment, create the order and notify fulfilment - across four independently deployed services. Which transaction strategy fits?

    2 min answer distributed-transactionssagatwo-phase-commitalibaba