Search: train

Raft Consensus Algorithm Low-Level Design: Leader Election, Log Replication, and Safety Guarantees

⏱ 9 min read Raft is the consensus algorithm designed to be understandable. It powers etcd (Kubernetes backbone), CockroachDB, TiKV, and many other systems […] Read article

Apr 17, 2026 System Design

Snapshot Isolation Low-Level Design: Read View Construction, Write-Write Conflict Detection, and MVCC Integration

⏱ 9 min read Snapshot isolation (SI) is the transaction isolation level used by PostgreSQL (as its default), Oracle, SQL Server, and many distributed […] Read article

Apr 17, 2026 System Design

Gossip Protocol Low-Level Design: Fan-Out Propagation, Convergence, Anti-Entropy, and Failure Detection

⏱ 9 min read The gossip protocol is the distributed systems equivalent of rumor spreading: each node periodically shares information with a small random […] Read article

Apr 17, 2026 System Design

Service Registry Low-Level Design: Registration, Health Monitoring, and Client-Side Discovery

⏱ 7 min read A service registry is the backbone of dynamic service discovery in microservice architectures. Rather than hardcoding service endpoints, every instance […] Read article

Apr 17, 2026 System Design

TLS Certificate Manager Low-Level Design: Issuance, Rotation, ACME Protocol, and Multi-Domain Support

⏱ 8 min read A TLS certificate manager automates the full lifecycle of digital certificates: issuance via ACME protocol, storage with encrypted private keys, […] Read article

Apr 17, 2026 System Design

Vector Database Low-Level Design: Embeddings Storage, ANN Search, and Hybrid Filtering

⏱ 9 min read A vector database stores high-dimensional embedding vectors and enables fast approximate nearest neighbor (ANN) search — finding the top-K vectors […] Read article

Apr 17, 2026 System Design

Document Store Low-Level Design: Schema Flexibility, Indexing, and Query Engine

⏱ 11 min read Document Store System: Overview A document store persists and retrieves arbitrary JSON documents. Unlike relational databases, it does not enforce […] Read article

Apr 17, 2026 System Design

Spell Checker System Low-Level Design: Edit Distance, Noisy Channel Model, and Context-Aware Correction

⏱ 9 min read Spell Checker System: Overview A spell checker takes an input word (potentially misspelled) and returns a ranked list of correction […] Read article

Apr 17, 2026 System Design

User Activity Feed Low-Level Design: Event Ingestion, Fan-Out, and Personalized Ranking

⏱ 8 min read User Activity Feed: Overview A user activity feed aggregates events from actors a user follows and surfaces them in reverse-chronological […] Read article

Apr 17, 2026 System Design

ML Feature Store Low-Level Design: Feature Ingestion, Online/Offline Serving, and Point-in-Time Correctness

⏱ 8 min read What Is an ML Feature Store? An ML feature store is a centralized system for computing, storing, versioning, and serving […] Read article

Apr 17, 2026 System Design