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Feature Engineering and Feature Stores Questions

Designing, building, and operating feature engineering pipelines and feature store platforms that enable large scale machine learning. Core skills include feature design and selection, offline and online feature computation, batch versus real time ingestion and serving, storage and serving architectures, client libraries and serving APIs, materialization strategies and caching, and ensuring consistent feature semantics and training to serving consistency. Candidates should understand feature freshness and staleness tradeoffs, feature versioning and lineage, dependency graphs for feature computation, cost aware and incremental computation strategies, and techniques to prevent label leakage and data leakage. At scale this also covers lifecycle management for thousands to millions of features, orchestration and scheduling, validation and quality gates for features, monitoring and observability of feature pipelines, and metadata governance, discoverability, and access control. For senior and staff levels, evaluate platform design across multiple teams including feature reuse and sharing, feature catalogs and discoverability, handling metric collision and naming collisions, data governance and auditability, service level objectives and guarantees for serving and materialization, client library and API design, feature promotion and versioning workflows, and compliance and privacy considerations.

HardTechnical
0 practiced
Design approaches for protecting sensitive information used in feature engineering. Compare role-based access control with attribute-based access control, data masking and tokenization, differential privacy for aggregate features, federated feature computation, and secure enclave approaches. Discuss trade-offs in model utility, auditability, and operational complexity.
MediumTechnical
0 practiced
Design the API contract for an online feature lookup service that supports typed schemas, vector features (embeddings), TTLs, fallback semantics, and request tracing. Provide example JSON request and response shapes, error codes, and describe how trace IDs and per-feature metadata such as last_updated and version are surfaced for observability.
HardTechnical
0 practiced
Describe and provide pseudocode for an algorithm that performs hybrid streaming plus batch incremental recomputation for a complex feature DAG. Some nodes are stateful streaming aggregations, others are expensive batch joins. The algorithm should minimize recompute cost, guarantee eventual correctness, handle out-of-order and late data, and support periodic reconciliation.
HardTechnical
0 practiced
At an organization with multiple ML teams, metric and feature naming collisions occur where different teams use the same feature name for different calculations. Design policies and technical controls to prevent and resolve metric collisions, including naming conventions, namespacing, semantic fingerprints, automated conflict detection, and migration strategies.
HardTechnical
0 practiced
Design an access-control and audit logging architecture for a feature store that satisfies enterprise security and compliance. The design should support RBAC and attribute-based policies, fine-grained per-feature and per-field controls, data masking for PII, immutable audit logs of accesses, and integration with identity providers. Describe enforcement points and policy storage.

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