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2707 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 areas2707 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 Architecture96 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 Architecture98 Streaming & Real-Time Data93 Data Governance & Semantics91 Frontend & Experience Architecture91 Edge, Mobile & IoT88 Regulatory & Data Protection Architecture90 Assurance, Audit & Model Risk98
Difficulty Any beginner intermediate advanced

63 questions in Edge, Mobile & IoT.

  1. Constrained Protocols advanced

    An MQTT 5 broker cluster serving 120,000 sensors starts alerting on disk at 03:00 every night, and the oldest of those alerts is three weeks old. Publish rate is flat at roughly 900 messages per second, connected clients sit at 118,000, and the broker reports 340,000 sessions and rising. No messages are being dropped yet. What failed, and which design decision made it possible?

    3 min answer mqttsessionsbrokerqueueing
  2. CRDTs advanced

    A collaborative field-notes app uses a CRDT set per project so devices can edit offline and merge without a server decision. Two years in, projects that are heavily edited take 40 seconds to open on a mid-range phone and the local database is 900 MB. Nothing has failed. What is happening, and what would you have designed differently?

    3 min answer crdtstombstonesmetadatafigma
  3. CRDTs advanced

    A collaborative product must let several devices edit the same records, including offline. When are CRDTs the right answer, and when is server authority simpler?

    2 min answer linearcrdtsyncconflicts
  4. CRDTs advanced

    A team proposes CRDTs for a collaborative document editor. What do you check before agreeing?

    2 min answer crdtcollaborationtradeoffs
  5. CRDTs advanced

    An inspection app keeps each site's checklist in an observed-remove set CRDT and synchronises by sending the whole replica state on every reconnect. 6,000 devices on cellular, roughly 40,000 elements per site set, about eight reconnects a day. Roughly how many bytes per device-day, and what does the number rule out?

    2 min answer crdtsor-setdelta-statebandwidth
  6. CRDTs advanced

    Conflict-free replicated data types guarantee convergence without coordination. What do they cost, and when is the guarantee not enough?

    1 min answer crdtsconvergencecollaborationmetadata
  7. Device Identity advanced

    A fleet of devices has certificates expiring in two years. What must be true today for that not to be an incident?

    2 min answer device-identityrotationprovisioningrevocation
  8. Device Identity advanced

    Design identity for devices that must authenticate to a platform for years, without a human present.

    1 min answer device-identitycertificatesrotationprovisioning
  9. Device Identity advanced

    How should device identity be established and maintained for a fleet, and what fails when it is done casually?

    2 min answer iotidentityprovisioningattestation
  10. Device Identity advanced

    You inherit an IoT fleet of 80,000 devices whose client certificates all expire in fourteen months. What do you do?

    2 min answer iotcertificatesrotationrisk
  11. Device Provisioning advanced

    A fleet of connected devices needs credentials. What does secure provisioning require, and what is the failure that ends the programme?

    2 min answer atheridentityprovisioningrotation
  12. Device Provisioning advanced

    Design provisioning for devices manufactured in volume and deployed by non-technical installers.

    1 min answer provisioningbootstrapsupply-chainidentity