WHATWG Living Standards
WHATWG
Browsers implement WHATWG — not versioned W3C snapshots. HTML, Fetch, and URL all live here.
What It Is
Maintains continuously-updated living standards for the web platform core: HTML, DOM, Fetch, URL, Streams, Storage, Encoding, WebSockets.
Taxonomy
Flat list of living standards (no version numbers)
Top-Level Categories
Master Catalog
Sub-Indexes & Guides
Maintains the living standards for the web platform: HTML, DOM, Fetch, URL, Streams, and more. These are continuously updated living documents, not versioned snapshots.
View all bodies →Curated specs from WHATWG
Browsers parse URLs per this standard, not raw RFC 3986. Critical for client-side routing, form encoding, and cross-origin behavior.
Every browser-side API call to a different origin hits CORS. Misconfigured CORS is a top source of dev frustration and security holes.
The spec behind every HTML page, form, and browser API. The canonical reference for how browsers actually parse and process HTML.
Every frontend framework (React, Vue, Svelte) ultimately produces DOM operations. Understanding the event model and tree structure prevents subtle bugs.
Every fetch() call and XHR request is governed by this spec. It also defines CORS behavior in detail.
Every component framework (React, Vue, Lit, Angular) either compiles to or interacts with these primitives. Shadow DOM is how browsers isolate component internals. Understanding the native model prevents framework lock-in.
The simplest client-side persistence. Used everywhere for auth tokens, user preferences, feature flags, and cross-tab state. Know the 5 MB limit, synchronous blocking, and origin scoping rules.
Any CPU-intensive work (parsing, compression, crypto, WASM) must run off the main thread to keep UI responsive. Workers are the browser's concurrency primitive — understand their message passing model and limitations (no DOM access).
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