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.
8 questions
2 complete public walkthroughs
#025Locked
Evolve a public API for five years without freezing the product
Balance compatibility, semantic versioning, deprecation, client capability, and operational evidence for an API customers cannot upgrade on command.
IntermediateAPIs & Events45 min
Api DesignSchema EvolutionChange Management
#026Locked
Deliver webhooks with semantics customers can actually prove
Design at-least-once delivery, ordering domains, signatures, replay, customer diagnostics, and provider-side backpressure without promising exactly once.
AdvancedAPIs & Events50 min
Event DrivenIdempotencySecurity
#027Locked
Evolve event schemas across forty teams without central paralysis
Combine compatibility rules, ownership, consumer evidence, contract tests, and exception governance for a large event ecosystem.
AdvancedAPIs & Events55 min
Schema EvolutionEvent DrivenGovernance
#028Locked
Coordinate a long-running workflow across unreliable external partners
Model durable state, deadlines, ambiguous outcomes, compensation, and operator intervention for workflows that outlive requests and deployments.
AdvancedAPIs & Events55 min
Distributed TransactionsIdempotencyReconciliation
#029Locked
Design idempotency across HTTP, queues, callbacks, and batch replay
Define one business-operation identity and outcome contract across transports whose retry and acknowledgment models do not align.
AdvancedAPIs & Events60 min
IdempotencyEvent DrivenConsistency
#030Locked
Contract batch and streaming results so they stop disagreeing silently
Unify semantics, event time, late data, versioning, and reconciliation when real-time and historical pipelines produce the same business metric.
AdvancedAPIs & Events60 min
Event DrivenBackfillsConsistency
#031Locked
Integrate an acquired platform without creating a permanent distributed monolith
Choose boundaries, identity, data ownership, and migration sequence under business pressure while preserving reversibility and team autonomy.
AdvancedAPIs & Events65 min
Change ManagementApi DesignOrganizational Design
#032Locked
Enforce global API quotas without turning fairness into a single-region bottleneck
Design hierarchical global and regional quota allocation with bounded overshoot, borrowing, outage behavior, and commercially explainable fairness.
ExpertAPIs & Events75 min
Admission ControlMulti TenancyActive Active
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.