/System Design

System Design Interview Cheat Sheet

tl;dr: “The system design questions are subjective. This cheat sheet is a work in progress and is written based on my research on the topic.” Topics include databases, API design, capacity planning, high level design, design deep dives, and more.

featured in #403

Tag Systems

- Hillel Wayne tl;dr: "I’ve tried to write a blog post on tag systems for years now... The problem is that there’s just so much to them, so many different approaches and models and concerns that trying to be comprehensive and rigorous is an exercise in madness... So screw it. These are my non-comprehensive, poorly-researched thoughts on tag systems. This is not about implementation of tag systems, just their design."

featured in #386

McDonald’s Event-Driven Architecture: The Data Journey And How It Works

- Vamshi Krishna Komuravalli Damian Sullivan tl;dr: Here is a typical data flow of how events are reliably produced and consumed from the platform: (1) Initially, an event schema is defined and registered in the schema registry. (2) Applications that need to produce events leverage producer SDK to publish events. (3) When an application starts up, an event schema is cached in the producing application for high performance. The authors continue to discuss how data flows through the system.

featured in #380

Demystifying Software Architecture Patterns

- Rahul Garg tl;dr: "The 3 most talked about patterns are Clean, Hexagonal, and Onion Architecture... all define a loosely coupled testable system that avoids any direct dependencies in terms of implementation, yet do so using their own terminology and each with specific nuances. They all suggest approaches to make software architectures more manageable and testable." Rahul looks at each as well as key architectural takeaways applicable regardless of approach.

featured in #358

What Happens When You Swipe A Credit Card? 

- Alex Xu tl;dr: "Visa, Mastercard, and American Express act as card networks for clearing and settling funds. The card acquiring bank and the card issuing bank can be – and often are – different. If banks were to settle transactions one by one without an intermediary, each bank would have to settle the transactions with all the other banks. This is quite inefficient."

featured in #335

Horrible Edge Cases To Consider When Dealing With Music

- Julien Voisin tl;dr: Julien highlights some of the challenges: "Weird" album names, albums without names, confusing names, long tracks up to 23 hours, tracks with different versions and more. Julien also links to the DB schema to show how to "tame this madness."

featured in #305

Root Cause Of Failure, Root Cause Of Success

- Lorin Hochstein tl;dr: “Root cause of failure” doesn’t make sense in the context of complex systems failure, because a collection of control processes keep the system up and running. A system failure is a failure of this overall set of processes." Lorin draws an analogy to illustrate this and points to the fact that if there's no root cause of success, why should there be one for failure.

featured in #251

AuthZ: Carta’s Highly Scalable Permissions System

- Aaron Tainter tl;dr: Aaron had to build a system that was scalable, fast & generic enough for any new products. Permission systems that are too simple lack the features to "support fine-grained access on single resources," and too complex the system might unravel a "whole policy of attribute-based permissions." Aaron runs through the creative approach taken.

featured in #235