Mithril.js JavaScript Framework

Mithril.js is a modern client-side JavaScript framework for building Single Page Applications, known for its extremely small size (under 10 KB gzipped), high performance, and pragmatic API. Created by Leo Horie in 2014, Mithril has over 14,000 stars as of 2026 and is used by major companies including Vimeo and Lichess (the popular online chess platform serving millions of games daily). Key features include: virtual DOM (efficient diffing and patching algorithm that updates only the minimum DOM nodes, achieving high rendering performance comparable to or better than React), component system (functional and class-based components with lifecycle methods including oninit, oncreate, onupdate, and onremove), hyperscript API (a terse, chainable function for creating virtual DOM nodes with tag names, attributes, and children: m('div.class', {onclick: fn}, 'text')), routing (built-in client-side router with parameterized routes, query strings, and route guards without external dependencies), XHR utilities (built-in HTTP request API with promise-based interface, JSON handling, and request cancellation), streaming (reactive data streams for functional reactive programming patterns with map, fold, and combine operations), extremely small footprint (less than 10 KB minified and gzipped with zero dependencies, making it ideal for bandwidth-constrained environments), TypeScript support (type definitions available for TypeScript projects), JSX compatibility (optional Babel plugin for JSX syntax support), performance benchmarks (consistently ranking among the fastest frameworks in rendering and update benchmarks), and ecosystem (community-driven plugins and integrations with testing frameworks and build tools).