Low Level Design: Column Store Database
3 min read Column Storage Basics In a column store, each column is stored separately on disk. This enables: Reading only the columns […] Read article
System Design
System Design
Low Level Design: Consensus Protocol Service
4 min read Consensus Protocol Service: Raft Raft is a consensus algorithm designed to be understandable. It decomposes consensus into relatively independent subproblems: Read article
System Design
Low Level Design: Vector Clock Service
3 min read Vector Clock Service Vector clocks track causality in distributed systems without requiring synchronized physical clocks. Each node maintains a vector Read article
System Design
Low Level Design: CRDT (Conflict-Free Replicated Data Types)
4 min read CRDT: Conflict-Free Replicated Data Types CRDTs are data structures that guarantee strong eventual consistency: any two replicas that have received Read article
System Design
Low Level Design: Web Crawler
2 min read URL Frontier Priority queue of URLs to crawl, prioritized by PageRank estimate + freshness. CrawlJob Table CrawlJob ( id, url, Read article
System Design
Low Level Design: Sitemap Generator Service
2 min read Sitemap XML Format urlset with url entries: loc, lastmod, changefreq, priority. Sitemap Index For sites with >50K URLs, generate multiple Read article
System Design
Low Level Design: Link Checker Service
2 min read Data Model CheckJob Table CheckJob ( id, target_domain, status: queued/running/completed, started_at, completed_at, total_links, broken_count ) LinkResult Table LinkResult ( id, Read article
System Design
Low Level Design: Search Query Parser
2 min read Query Syntax A full-featured query parser supports: AND/OR/NOT boolean operators, phrase queries (exact ordered match), field-specific search (title:python), wildcards (* Read article
System Design
Low Level Design: Invoice Service
4 min read Invoice Service: Overview An invoice service manages the full lifecycle of invoices: creation, line items, tax, PDF generation, payment collection, Read article
System Design
Low Level Design: Ledger Service
3 min read Double-Entry Accounting Primer Every financial event produces at least two journal lines: one debit and one credit. The sum of Read article
System Design
Low Level Design: Payout Service
4 min read Overview A payout service disburses funds to recipients via multiple rails: ACH (batch, 1-2 day settlement), wire (same-day, high fee), Read article
System Design
Low Level Design: Feature Flag Targeting Service
4 min read Feature Flag Targeting Service: Low Level Design A feature flag targeting service lets teams release features safely by controlling visibility Read article
System Design
Low Level Design: Experimentation Platform
4 min read Experimentation Platform: Low Level Design An experimentation platform enables A/B and multivariate tests with rigorous statistical guarantees. This design covers Read article
System Design
Low Level Design: ML Model Serving Service
5 min read ML Model Serving Service: Low Level Design An ML model serving service provides versioned, low-latency online inference alongside batch prediction, Read article
System Design
Low Level Design: Operational Transform Sync
2 min read OT for Text Operations are insert(pos, text) and delete(pos, len). Transformation Function transform(op1, op2) adjusts positions of concurrent ops to Read article