Trade-off discipline
State what wins, what loses, and which new evidence would reverse the choice.
Architecture Judgment Index
75 system design decisions beyond the standard question bank
Built for Staff, Principal, Architect, and senior engineering leadership interviews. Practice ambiguous trade-offs, migrations, blast-radius reasoning, multi-region consistency, cost, security, and the judgment behind an architecture review.
75
original questions
10
decision domains
2
complete samples
35–90m
interview depth
10 Senior · 30 Staff · 25 Principal · 10 Distinguished
What the interview is really testing
Architecture judgment under incomplete information
These are not component-recitation prompts. Each scenario forces a candidate to identify the decision, make assumptions explicit, protect invariants, plan failure and recovery, price the options, and lead a realistic change from the system and organization that already exist.
Failure and recovery
Define blast radius, degraded behavior, reconciliation, rollback, and operational proof.
Evolutionary delivery
Move from the current architecture through observable, reversible stages instead of a flag day.
Staff-level influence
Connect technical decisions to ownership, incentives, cost, policy, and cross-team execution.
Coverage
Ten decision domains
Balanced across distributed systems, data, reliability, platform, security, performance, evolution, economics, and leadership.
Distributed Systems & Scale
Partitioning, coordination, overload, state movement, and blast-radius decisions in mature distributed systems.
Data Architecture & Consistency
Transaction boundaries, online migrations, residency, backfills, reconciliation, and truthful derived data.
Reliability, Resilience & Recovery
Cascades, brownouts, rollbacks, regional evacuation, disaster recovery, and measurable dependency risk.
APIs, Events & Integration
Long-lived contracts, event evolution, partner workflows, delivery semantics, acquisitions, and global fairness.
Cloud Infrastructure & Platforms
Paved roads, control planes, deployments, identity, scheduling, capacity, and governed self-service platforms.
Security, Privacy & Multi-Tenancy
Isolation boundaries, key management, deletion, zero trust, side channels, audit evidence, and privileged access.
Performance, Observability & Capacity
Tail latency, SLO policy, telemetry economics, uncertain demand, workload isolation, and silent failure detection.
Architecture Evolution & Migrations
Monolith evolution, stranglers, protocol changes, ownership boundaries, debt portfolios, and reversible decompositions.
Cost & Operational Efficiency
Reliability-aware savings, unit economics, tiering, build-versus-buy, carbon, egress, and commitment risk.
Architecture Leadership & Decisions
Decision quality, cross-team alignment, compliance trade-offs, program recovery, platform retirement, and impact.
7 questions
2 complete public walkthroughs
#048Locked
Define SLOs and error-budget policy for a product with unequal journeys
Choose customer-centered indicators, windows, targets, and policy actions without averaging away critical tenants or turning SLOs into vanity dashboards.
IntermediatePerformance & SLOs50 min
SloError BudgetsObservability
#049Locked
Diagnose a p99 regression that every average says does not exist
Localize tail amplification across cohorts, fan-out, queues, pauses, and dependencies while avoiding coordinated omission and misleading percentiles.
AdvancedPerformance & SLOs55 min
PerformanceObservabilityCapacity Planning
#050Locked
Design observability that stays useful under cardinality and cost pressure
Choose metrics, traces, logs, exemplars, retention, and tenant debugging paths without letting unbounded labels bankrupt or disable telemetry.
AdvancedPerformance & SLOs55 min
ObservabilityCloud CostMulti Tenancy
#051Locked
Define launch capacity when every demand forecast is uncertain
Convert demand ranges and workload units into tested capacity, admission policy, ramp gates, and business contingency for a high-visibility launch.
AdvancedPerformance & SLOs55 min
Capacity PlanningLoad SheddingCloud Cost
#052Locked
Preserve operational truth through telemetry network partitions
Design local buffering, protected signals, clock and sequence semantics, later merge, and incident visibility when the central telemetry path is broken.
AdvancedPerformance & SLOs60 min
ObservabilityIncident ResponseActive Active
#053Locked
Design performance isolation for mixed interactive and analytical workloads
Protect latency SLOs from scans, compaction, and background work using admission, pools, replicas, workload contracts, and resource accounting.
AdvancedPerformance & SLOs60 min
PerformanceMulti TenancyCapacity Planning
#054Locked
Detect silent data loss in a multi-stage pipeline before customers do
Design end-to-end completeness signals, invariants, lineage, quarantine, and repair when every component reports healthy while records disappear.
ExpertPerformance & SLOs75 min
ObservabilityReconciliationEvent Driven
Build the primitives behind the decisions
Pair the index with InterviewVector's Distributed Systems field manual, system design case studies, and the AI Architect track.