Interview Prep Guide (HLD & LLD)

System design interviews (typically 45–60 minutes) are open-ended discussions evaluate how you analyze trade-offs, manage ambiguity, and structure architectural plans. Use this guide to direct your preparation.

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📚 Recommended Books

Building a solid theoretical foundation is the first step toward high-quality design choices.

1. System Design Interview (Vol. 1 & 2) — Alex Xu (ByteByteGo)

Two volumes that walk through real system design questions with detailed breakdowns. Excellent for understanding how to structure answers. This is widely considered the #1 starting point for anyone preparing for system design interviews.

2. Designing Data-Intensive Applications — Martin Kleppmann

More theoretical than the others, but it builds the deep mental model that separates good answers from great ones.

• Focus Chapters: Focus on chapters covering Replication, Partitioning, and Transactions.

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🌐 Online Platforms & Courses

3. ByteByteGo (bytebytego.com)

ByteByteGo is a leading learning platform for system design interview preparation, well known for its visual, practical guides and real-world system architecture examples. Their YouTube channel also has free, well-illustrated breakdowns.

4. Educative — Grokking Modern System Design

Built by FAANG engineers, it is a valuable course for system design interview preparation with interactive, hands-on content.

5. Exponent (tryexponent.com)

Great for mock interviews and company-specific prep. Real system design interview questions from 2026 include things like:

• Designing a high-level system for a large language model (LLM) serving cluster.
• Distributing huge files to thousands of physical machines.
• Designing safeguards for an AI system that can take actions on behalf of a user.

6. DesignGurus / Hello Interview

Hello Interview's "System Design in a Hurry" is built by former FAANG hiring managers — if you have a week or less before your interview, this is the fastest way to get interview-ready.

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🗺️ Suggested Learning Path

Use this structured schedule to progress from foundational concepts to live mock interviews:

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💡 Pro Tips for 2026

1. Expect AI System Design Loops

If you're interviewing at any company that ships AI features, expect at least one prompt involving:

• LLM Serving: GPU memory footprints, request batching (continuous batching), kv-cache management, and latency optimizations.
• Embedding Pipelines: Vector databases, chunking strategies, indexing algorithms (HNSW, IVF), and ingestion at scale.
• GPU Resource Management: GPU scheduling, orchestration, and compute allocation.
• Refer to the Generative AI interview prep hub for details.

2. The Conversation is the Rubric

A system design interview is a 45–60 minute conversation where there is no single correct answer — the interviewer is evaluating how you think, not checking your diagram against a rubric. So practice reasoning out loud, not just memorizing answers.