Prepare for Interview
End-to-end preparation for senior technical interviews — behavioral, coding, system design, and object-oriented rounds.
Prep Plans
Phase-based plans for interview prep — what to do, in what order, and what to cut when time is short.
Behavioral
Structuring stories, answering leadership principle questions, and showing impact without performing it.
Coding
Problem-solving under time pressure, reasoning out loud, and communicating your approach clearly.
System Design
Scoping, reasoning about tradeoffs, and navigating the open-ended structure of senior design rounds.
Object-Oriented Design
Designing small-to-medium systems at the class and interface level — the interview-style OO round.
All articles in this category
Walkthrough: Designing a Top K System
A candidate's-eye walkthrough of the top-K / trending / leaderboard system design question — starting from a naive DB, evolving through caching and streaming, and arriving at Count-Min Sketch + Heavy Hitters with sliding windows.
Walkthrough: Designing a Geospatial Matching System
A candidate's-eye walkthrough of the Uber/Yelp-style geospatial system — Geohash vs quad-tree indexing, high-QPS driver-location ingestion, and radius matching.
Reference: Database Indexing
A reference on B-Tree vs LSM-Tree storage engines, composite index column ordering, covering indexes, and where secondary indexes create hot shards.
Reference: Common System Design Decisions
A fast-lookup catalog of recurring system design choices — storage, performance, architecture, reliability — each with a default and when to switch away from it.
Walkthrough: Designing a Distributed Job Scheduler
A candidate's-eye walkthrough of the distributed job scheduler question — covering cron jobs, delay queues, DAG orchestration, and the tick problem at 1B+ tasks/day.
Guide: The Senior Coding Interview at Big Tech
The operational manual for running a big-tech coding round — one continuous interview workflow from understanding the problem to handling follow-ups, with the senior move at each step.
Plan: Senior Backend Software Engineer Interview Prep
A 12-week preparation plan for backend engineers targeting Google L5, Meta E5, Amazon L6, Senior SWE, and equivalent roles.
List: The 60-Problem LeetCode List for Senior Big-Tech Loops
A curated ~60-problem LeetCode list for big-tech loops, organized by a problem-recognition framework — eight categories, a recognition order, per-company notes, and a ranked "what's next" tier.
Plan: 9-Week System Design Interview Prep
A dependency-ordered system design prep plan for senior backend engineers — rubric, company calibration, walkthroughs, follow-up strategy, and production thinking.
Walkthrough: Designing a CDN
A full candidate's-eye walkthrough of the CDN system design question — anycast vs DNS routing, cache hierarchies and origin shielding, invalidation, and flash-crowd survival.
Walkthrough: Designing a Distributed Database
A full candidate's-eye walkthrough of the distributed SQL database question — range partitioning with per-range consensus, distributed transactions over Raft, MVCC timestamps, and multi-region placement.
Walkthrough: Designing a Distributed Key-Value Store
A full candidate's-eye walkthrough of the Dynamo-style key-value store question — consistent hashing, quorum reads and writes, vector clocks, hinted handoff, and anti-entropy repair.
Walkthrough: Designing a Distributed Lock
A full candidate's-eye walkthrough of the distributed lock question — Redis vs consensus-backed locks, sessions and ephemeral ownership, fencing tokens, and leader election.
Walkthrough: Designing a Distributed Queue
A full candidate's-eye walkthrough of the Kafka-style distributed queue question — log vs queue semantics, partitioned ordering, consumer groups, replay, and backpressure.
Walkthrough: Designing a File Storage & Sync Service
A full candidate's-eye walkthrough of the Dropbox-style file storage question — chunking and content addressing, metadata/content separation, delta sync, dedup, and conflict handling.
Walkthrough: Designing a Metrics & Monitoring System
A full candidate's-eye walkthrough of the metrics system design question — time-series data modeling, ingest at millions of samples per second, cardinality, downsampling, and alerting.
Walkthrough: Designing a Recommendation System
A full candidate's-eye walkthrough of the recommendation system design question — the recall/ranking funnel, feature stores, embedding retrieval, and the feedback loop.
Reference: Capacity Estimation
A short reference on interview capacity math — QPS, storage, and bandwidth estimates, the numbers worth memorizing, and turning arithmetic into design conclusions.
Reference: Consistency Models
A short reference on consistency guarantees from linearizable to eventual — what each promises, what it costs, and how CAP and PACELC frame the choice.
Reference: Partitioning Strategies
A short reference on hash, range, and consistent-hash partitioning — how each distributes data, what breaks with each, and how to pick a partition key.
Reference: Queue Delivery Semantics
A short reference on at-most-once, at-least-once, and exactly-once delivery — where each guarantee actually comes from, and what replay and idempotency add.
Reference: Replication Strategies
A short reference on leader-follower, multi-leader, and leaderless replication — failure behavior, lag anomalies, and quorum arithmetic for each.
Guide: The AI-Native Coding Interview
How to prepare for the AI-enabled coding interview — which companies use it, what questions look like, and how to demonstrate the judgment that AI can't.
Guide: Amazon's Logical & Maintainable Coding Interview
How to prepare for Amazon's L&M round — the coding interview that grades you on clean code, extensibility, and design patterns instead of algorithms.
Walkthrough: Designing a News Feed
A full candidate's-eye walkthrough of the news feed system design question — from the push vs pull fan-out decision through the celebrity problem, ranking, and failure modes.
Reference: NoSQL Hot Key Mitigation Patterns
A short reference on hot key patterns in distributed NoSQL systems — what causes them, and the static and dynamic strategies for mitigating them.
Guide: Managing Energy During Interview Loops
An interview loop is an energy budget, not a time budget. Where your cognitive resources go in the two weeks before loop day matters more than how much you study.
Guide: The SRE Systems (OS) Interview
How to prepare for the SRE/Production Engineering systems interview — the OS internals breadth they probe, and the troubleshooting methodology they actually grade.
Framework: Structuring Leadership Stories for Behavioral Rounds
A framework for the senior+ IC leadership story — what makes a story actually demonstrate leadership signal, and the three shapes that land.
Guide: The Project Management Interview for Engineers
How to prepare for the project-management round in an engineering loop — the four areas it scores and how to tell project stories that show execution, not just participation.
Framework: An OO Design Interview Framework
A four-step framework for OO design interviews — narrow scope, model the core entities, sketch the API, then defend extension. Most candidates name classes too early.
Walkthrough: Designing an Auction System
A candidate's-eye walkthrough of an online auction system — from clarifying questions through bid serialization, real-time fan-out, closing-time correctness, and proxy bidding.
Walkthrough: Designing a Collaborative Editor
A candidate's-eye walkthrough of a Google Docs-style collaborative editor — from clarifying questions through OT vs CRDT, presence, persistence, and offline editing.
Guide: Last-Minute System Design Review Checklist
A concrete checklist for the 24 hours before a system design interview — what to review, what to skip, and the moves that recover the most points if you only have one evening.
Walkthrough: Designing an Order Processing System
A candidate's-eye walkthrough of an Amazon-style order processing system — from clarifying questions through saga orchestration, idempotency, inventory reservation, and payment compensation.
Walkthrough: Designing a Flash Deal System
A candidate's-eye walkthrough of the flash-sale system design — from clarifying questions through inventory contention, oversell prevention, surge handling, and degradation strategy.
Walkthrough: Designing a Video Streaming Platform
A candidate's-eye walkthrough of a YouTube-style video streaming system — from clarifying questions through upload pipeline, ABR transcoding, CDN delivery, and metadata.
Reference: Consecutive Activity & Retention Aggregation
A reference on computing streaks and retention over massive event streams — pre-aggregation, state slimming, and the bitmap, gaps-and-islands, and streaming techniques per time grain.
Reference: Distributed Transaction Patterns
A deep reference on distributed transaction patterns — 2PC, 3PC, and saga — their sequences, failure modes, and when to reach for each.
Framework: The Behavioral Interview for Senior+
A framework for senior+ behavioral interviews — what's actually being tested, why STAR fails at this level, and the four signals that drive the outcome.
Guide: Meta Signals Decoded
A practical guide to the seven behavioral signals Meta calibrates against — and how to land each one in the loop without sounding rehearsed.
Walkthrough: Designing an AI Agent Orchestration System
A candidate's-eye walkthrough of AI agent orchestration — tool dispatch, state management, safety rails, and the failure modes that matter when LLMs take actions.
Walkthrough: Designing a Distributed Cache
A candidate's-eye walkthrough of the distributed cache system design — from consistent hashing through replication, eviction, and the failure modes that matter.
Walkthrough: Designing a Notification System
A candidate's-eye walkthrough of the notification system design — multi-channel delivery, fan-out, prioritization, and the failure modes that matter.
Framework: Thinking About Tradeoffs in System Design
A framework for reasoning about system design tradeoffs — how to name the axes, use context to break the tie, and commit to an imperfect choice by naming its cost.
Walkthrough: Designing a Vector Database
A candidate's-eye walkthrough of the vector database system design — HNSW indexing, sharding high-dimensional vectors, hybrid search, and the failure modes that matter.
Walkthrough: Designing an LLM Serving Platform
A candidate's-eye walkthrough of the LLM inference platform design — continuous batching, KV cache, GPU sharding, autoscaling, and the failure modes that actually matter.
Walkthrough: Designing a Full Ranking System
A candidate's-eye walkthrough of the full-ranking / arbitrary-rank lookup system design question — when top-K isn't enough, why sorted sets don't scale to billions, and how histograms, bucketed counts, and offline precomputation compose into a multi-tier design.
Walkthrough: Designing a Post Search System
A candidate's-eye walkthrough of the post search system design question — indexing, sharding, two-stage ranking, visibility, freshness, and the failure modes that matter.
Walkthrough: Designing a Rate Limiter
A full candidate's-eye walkthrough of the rate limiter system design question — from single-node DB-based counting through distributed Redis counters, failure handling, multi-tenant rule engines, and cross-region extension.
Reference: API Design Patterns
A short reference on REST vs gRPC, versioning, pagination, idempotency, and the small decisions that separate a designed API from an improvised one.
Reference: Cache Access and Invalidation Patterns
A reference on read/write caching patterns, invalidation strategies, and the classic failure modes — penetration, breakdown, avalanche — and how to avoid each.
Reference: Rate Limiting Algorithms
A short reference on the four canonical rate limiting algorithms — token bucket, leaking bucket, fixed window, and sliding window — with when to pick each.
Reference: Real-Time Connection Patterns
A short reference on HTTP polling, long-polling, SSE, WebSocket, WebRTC, and push notifications — which to reach for and why.
Reference: SQL vs NoSQL Schema Design
A short reference on when to pick SQL vs NoSQL, how to model schemas in each, and how to avoid hot keys.
Walkthrough: Designing a RAG System
A candidate's-eye walkthrough of the RAG system design interview — chunking, embeddings, hybrid retrieval, reranking, eval, and the failure modes that matter.
Walkthrough: Designing an Ad Click Aggregation System
A full candidate's-eye walkthrough of the ad click aggregation system design question — from ingestion and streaming windows through exactly-once semantics, anti-entropy, failure modes, and cross-region extensions.
Walkthrough: Designing a Chat System
A full candidate's-eye walkthrough of the chat system design question — from connection management and delivery guarantees through per-conversation ordering, offline notifications, and failure modes.
Walkthrough: Designing a URL Shortener
A full candidate's-eye walkthrough of the URL shortener system design question — from clarifying questions through ID generation, caching, analytics, and failure modes.