Frontend System Design

DevNotes

A practical reference for frontend system design — networking, security, performance, and everything in between.

Topics

Browse by topic, organized for quick lookup.

HTTP, WebSockets, protocols and how the browser talks to the network.

How frontend systems talk to each other and to the backend.

XSS, CSRF, SSRF, injection and defending the frontend.

Unit, integration and end-to-end testing strategy notes.

Rendering, bundling, caching and making things fast.

Client-side storage, caching layers and data strategies.

Observability, error tracking and monitoring the frontend.

Screen readers, keyboard nav, contrast and inclusive UI.

Service workers, sync and building for flaky networks.

Designing components and systems from first principles.