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LLM System InterviewHao Hoang · First edition, 2026Home

Front Matter

Title Page Contents Preface How to Use This Book For Candidates Preparing for Interviews For Engineers Building LLM Systems Notation and Symbols Acknowledgments About the Author

I · Overview and Interview Landscape

The LLM Systems Interview How to Approach an LLM System Design Question

II · Foundations: Transformer Architecture and Training Signals

Transformer Architecture Interview Essentials Hyperparameters You Will Be Asked to Justify Stability Tricks in Large-Scale Training

III · Mixture of Experts and Sparse Architectures

Why MoE Is Now Standard in Frontier Systems MoE Training and Systems Considerations

IV · GPUs, Kernels, and Single-Device Performance

GPU Architecture for LLM Engineers Making a Single GPU Go Fast Writing and Benchmarking Custom Kernels

V · Distributed Training: Parallelism at Scale

Multi-GPU and Multi-Node Fundamentals Parallelism Strategies

VI · Scaling Laws and Training Economics

Predictable Scaling for Interview Answers Chinchilla and Beyond

VII · Inference Systems

The Inference Workload Reducing the KV Cache Going Beyond the Transformer for Inference Speculative Decoding and Serving Optimizations Compression Techniques for Deployment

VIII · Data: The Real Differentiator

Pre-Training Data Pipelines Data Filtering and Deduplication Algorithms Mid-Training and Post-Training Data

IX · Evaluation

Designing an Evaluation Benchmarks You Must Know Validity, Contamination, and Real-World Use

X · Alignment and Post-Training

Supervised Fine-Tuning Preference-Based Alignment (RLHF)Reinforcement Learning from Verifiable Rewards

XI · End-to-End System Design Drills

Building a Production LLM Serving Stack Designing a Pre-Training Run from Scratch Designing a Fine-Tuning and Alignment Pipeline

Appendices

Napkin Math for LLM Interviews Common Interview Questions Checklists for System Design Answers Further Reading

Navigation

Reading Routes Source Index

Reading Routes

How to Use This Book

For Candidates Preparing for Interviews

For Engineers Building LLM Systems

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Original book: Hao Hoang · First edition, 2026
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