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
#041Locked
Design enterprise SaaS tenant isolation as a graduated set of boundaries
Match logical, resource, data, key, and cell isolation to tenant risk and economics without claiming one database row filter solves everything.
IntermediateSecurity & Tenancy55 min
Multi TenancySecurityBlast Radius
#042Locked
Rotate a multi-level encryption key hierarchy without losing availability
Design envelope-key versioning, lazy and bulk rewrap, compromise response, cache behavior, and evidence for billions of encrypted objects.
AdvancedSecurity & Tenancy55 min
EncryptionSecurityZero Downtime
#043Locked
Delete customer data across replicas, indexes, logs, and backups
Design a deletion state machine with lineage, tombstones, cryptographic erasure, retention exceptions, and proof across a sprawling data estate.
AdvancedSecurity & Tenancy55 min
PrivacyComplianceReconciliation
#044Locked
Build zero-trust boundaries around a legacy trusted network
Introduce identity, authorization, segmentation, and policy telemetry incrementally when legacy services assume network location equals trust.
AdvancedSecurity & Tenancy55 min
SecurityChange ManagementBlast Radius
#045Locked
Prevent cross-tenant side channels in a high-density shared service
Reason about timing, cache, resource, error, and telemetry leakage while preserving enough sharing for the service to remain economical.
AdvancedSecurity & Tenancy60 min
Multi TenancySecurityPerformance
#046Locked
Design an audit trail that survives privileged operator error
Make high-risk administrative actions attributable and tamper-evident even when the actor controls production systems or normal logging.
AdvancedSecurity & Tenancy60 min
AuditabilitySecurityIncident Response
#047Locked
Design an abuse-resistant privileged admin plane for global operations
Balance emergency speed with least privilege, just-in-time access, dual control, command safety, tenant scope, and compromise containment.
ExpertSecurity & Tenancy75 min
SecurityAuditabilityControl Plane
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.