Cards

One a day. System design, science, history, and whatever else was worth a second look. All 95 of them, newest first.

Vamana, small and barefoot, palm outstretched before Maveli, who stands crowned and open-handed under a golden umbrella, above a pookalam ringed with lamps

CultureAug 27, 2026

The King To Whom God Came Asking

culture kerala onam

Five Sangam landscapes — kurinji mountains, mullai forest, marutham fields, neithal shore, palai wasteland — each carrying a stage of love, and a sixth, kaikkilai, with no landscape at all

Tamil ThoughtAug 27, 2026

The Love With No Landscape

tamil-thought sangam poetry

The Rewrite That Never Ships — system design card, day 26, microservices: a proxy in front of a legacy system routes one endpoint at a time to new services until the old system serves nothing

MicroservicesDay 26Aug 27, 2026

The Rewrite That Never Ships

microservices system-design strangler-fig

The Search That Can't Spell — system design card, day 27, AI systems: BM25 keyword results and vector results merged by reciprocal rank fusion so an exact citation surfaces above essays about the concept

AI SystemsDay 27Aug 27, 2026

The Search That Can't Spell

ai-systems system-design rag

The Celebrity Who Breaks Your Feed — system design card, day 24, case study

Case StudyDay 24Aug 24, 2026

The Celebrity Who Breaks Your Feed

case-study scale system-design

Add One Server, Move Everything — system design card, day 25, networking: modulo hashing moves 80% of keys, consistent hashing moves 20%

NetworkingDay 25Aug 24, 2026

Add One Server, Move Everything

networking system-design consistent-hashing

Machiavelli's 1513 portrait beside the Joker, their matching quotes on broken promises, and the split into architecture or arson

PhilosophyAug 24, 2026

Machiavelli and the Joker

philosophy cinema power

The Consumer That Fell Behind Forever — system design card, day 23, kafka

KafkaDay 23Aug 23, 2026

The Consumer That Fell Behind Forever

consumer-lag kafka system-design

The Lock That Outlived Its Owner — system design card, day 22, distributed systems

Distributed SystemsDay 22Aug 22, 2026

The Lock That Outlived Its Owner

distributed-locks distributed-systems system-design

The Limit That Punishes Your Best Users — system design card, day 21, apis

APIsDay 21Aug 21, 2026

The Limit That Punishes Your Best Users

apis rate-limiting system-design

You Posted It. Then It Vanished. — system design card, day 20, databases

DatabasesDay 20Aug 20, 2026

You Posted It. Then It Vanished.

databases postgresql system-design

Say No Before You Have To — system design card, day 19, reliability

ReliabilityDay 19Aug 19, 2026

Say No Before You Have To

load-shedding reliability system-design

The Index You Added Made Writes Slower — system design card, day 18, databases

DatabasesDay 18Aug 18, 2026

The Index You Added Made Writes Slower

databases postgresql system-design

Your Agent Is A Confused Deputy — system design card, day 17, ai systems

AI SystemsDay 17Aug 17, 2026

Your Agent Is A Confused Deputy

ai ai-systems security

Everyone Asks At The Same Second — system design card, day 16, caching

CachingDay 16Aug 16, 2026

Everyone Asks At The Same Second

caching redis system-design

The Average User Doesn't Exist — system design card, day 15, foundations

FoundationsDay 15Aug 15, 2026

The Average User Doesn't Exist

foundations performance system-design

More Threads, Slower System — system design card, day 14, concurrency

ConcurrencyDay 14Aug 14, 2026

More Threads, Slower System

concurrency context-switching system-design

You Didn't Split It. You Stretched It. — system design card, day 13, microservices

MicroservicesDay 13Aug 13, 2026

You Didn't Split It. You Stretched It.

distributed-monolith microservices system-design

Why The First Request Is Always Slow — system design card, day 12, networking

NetworkingDay 12Aug 12, 2026

Why The First Request Is Always Slow

dns networking system-design

The Two Writes That Must Be One — system design card, day 11, kafka

KafkaDay 11Aug 11, 2026

The Two Writes That Must Be One

kafka system-design transactional-outbox

Why Uber Chose Hexagons — system design card, day 10, case study

Case StudyDay 10Aug 10, 2026

Why Uber Chose Hexagons

case-study system-design uber

Turning The Earth Into Words — system design card, day 10, distributed systems

Distributed SystemsDay 10Aug 10, 2026

Turning The Earth Into Words

distributed-systems geospatial system-design

The Retry That Charges Twice — system design card, day 9, apis

APIsDay 9Aug 9, 2026

The Retry That Charges Twice

apis idempotency system-design

The Outage That Starts After You're Saved — system design card, day 8, case study

Case StudyDay 8Aug 8, 2026

The Outage That Starts After You're Saved

case-study resilience system-design