Mithril

Minimalist client-side JavaScript framework for building single-page applications. Provides virtual DOM rendering, built-in routing and XHR utilities, and a small footprint under 10KB gzipped, with no build step required to get started.

Used by companies like Vimeo, Nike, and Fitbit, and powers open-source platforms such as Lichess and Flarum. Mithril.js stands out by bundling routing and XHR out of the box, unlike React where teams typically assemble third-party libraries, leading to more consistent project structure and faster onboarding. The same tutorial that teaches components, routing, and XHR takes about 10 minutes.

Key capabilities:

• Built-in routing with hashbang URLs and route parameter handling
• Built-in XHR utility with file uploads and authentication patterns documented
• Component-based architecture with lifecycle methods and key-based reconciliation
• Autoredraw system for reactive updates, touching only the DOM parts that change
• JSX support via Babel plugin, optional animation utilities and third-party integration guides

Teams choose Mithril.js when bundle size and load time matter, for SPAs on mobile or low-power devices, and when preferring a batteries-included approach over assembling a custom stack. Developers can include it from a CDN without a bundler or integrate it into existing builds. The framework supports IE11, Firefox ESR, and the last two versions of major browsers, with no polyfills required.