Design the manual review workflow

Quick Overview

Design the manual review workflow evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

Design the manual review workflow

Company: Roblox

Role: Software Engineer

Category: System Design

Difficulty: hard

Interview Round: Onsite

Design the human-in-the-loop review subsystem. Explain how review tasks are generated from detections; triage into queues by severity; reviewer UI requirements; SLAs; sampling and double-blind consensus for quality; gold-standard audits; escalation and requeueing; access control and privacy for sensitive audio; audit logs; and how reviewer feedback updates system thresholds, rules, and training data. Include capacity planning for reviewers and backlog control.

Quick Answer: Design the manual review workflow evaluates requirements, scale assumptions, API/data design, architecture, trade-offs, failure modes, and rollout in a realistic interview setting. A strong answer states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

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Roblox
Jul 31, 2025
hardSoftware EngineerOnsiteSystem Design
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Design the manual review workflow

System Design: Human-in-the-Loop Review Subsystem

Context

You are designing a human-in-the-loop (HITL) review subsystem for a large-scale safety platform that moderates user-generated content (UGC) across text, images, and audio (including live voice). Automated detectors (ML models and rules) generate “detections” with metadata (content IDs, model type, confidence, policy category, timestamps). Some detections require immediate enforcement; others need human review for accuracy, context, or policy interpretation.

Requirements

Design and explain the end-to-end HITL subsystem, covering:

  1. How review tasks are generated from detections (schema, deduplication, aggregation, idempotency, sampling).
  2. Triage into queues by severity with prioritization and dynamic aging.
  3. Reviewer UI requirements and ergonomics, including audio-specific needs.
  4. SLAs/SLOs per queue and breach handling.
  5. Sampling and double-blind consensus to ensure quality; inter-rater agreement.
  6. Gold-standard audits (honeypots), reviewer calibration, and performance scoring.
  7. Escalation paths and requeueing logic for ambiguous or time-sensitive items.
  8. Access control and privacy for sensitive audio and PII.
  9. Audit logs and tamper-evident trail.
  10. Feedback loop where reviewer decisions update model thresholds, rules, and training data.
  11. Capacity planning for reviewers and backlog control during surges.

State reasonable assumptions where necessary and be explicit about trade-offs.

Clarifying Questions to Ask Guidance

  • Clarify users, core use cases, read/write patterns, scale, latency, availability, and data retention.
  • State explicit assumptions before making sizing or architecture decisions.
  • Prioritize the functional path first, then address reliability, security, observability, and rollout.

What a Strong Answer Covers Guidance

  • A scoped requirements summary with concrete non-goals and success metrics.
  • API, data model, architecture, consistency, capacity, and operations.
  • Reasoned trade-offs among simple and scalable designs, including bottlenecks and failure modes.
  • A validation, monitoring, migration, and launch plan appropriate for the risk level.

Follow-up Questions Guidance

  • What breaks first at 10x traffic or data volume?
  • How would you degrade gracefully during dependency failures?
  • What metrics and alerts would prove the design is healthy after launch?

Submit Your Answer to Earn 20XP

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