State is data that changes over time. Where and how you manage state significantly impacts application architecture, performance, and complexity.
| UI State | Modal open, tab selected, form input | Local, ephemeral | | Server State | User data, products, posts | Remote, cached, async | | URL State | Page, filters, search query | Shareable, bookmarkable | | Browser State | localStorage, sessionStorage, cookies | Persistent, limited |
| Application State | Auth, theme, user preferences | Global, session-scoped |
Explains state management in web applications including client state, server state, URL state, and caching strategies. Use when discussing where to store state, choosing between local and global state, or implementing data fetching patterns. Source: kinfe123/fm-skills.