TinyJS: 6MB Desktop Apps via OS WebViews, No Chromium Bundling

Software engineer Tarwin Stroh-Spijer created TinyJS , an open-source JavaScript runtime for building tiny desktop applications on macOS, Linux, and Windows. Many apps occupy roughly 6 MB on disk, a stark contrast to the 150 MB baseline of Electron apps.

How TinyJS Achieves Its Small Footprint

TinyJS does not ship a browser engine. Instead it uses each operating system's built-in WebView component:

macOS → WebKit Windows → WebView2 (Chromium-based but shared system component)

Linux → WebKitGTK Because the rendering layer is provided by the OS, the TinyJS starter kit is only about 5.6 MB and the launcher adds roughly 1 MB ; the rest is developer code. The core runtime is txiki.js , an ultra-compact JavaScript engine written by Saúl Ibarra Corretgé, which makes Deno and Bun look like “giant objects” by comparison.

Comparison with Electron and Tauri

Electron

Electron bundles a full Chromium instance with every application, guaranteeing pixel-perfect cross-platform consistency but paying a heavy size penalty: even a minimal Electron app exceeds 150 MB . TinyJS accepts minor visual differences across platforms (due to each OS's rendering engine) in exchange for a 25× size reduction.

Tauri

Tauri also targets small binaries (~10 MB) but requires the developer to write the backend in Rust , adding a learning curve. TinyJS keeps the entire stack in JavaScript/TypeScript. Moreover, Tauri expects developers to import plugins one by one for features like dialogs, menus, tray icons, clipboard, and auto-updates, whereas TinyJS delegates those capabilities to the OS out of the box.

Core Architecture

No bundled HTTP server – TinyJS uses OS-level inter-process communication (IPC) for data transfer between the frontend (WebView) and the backend (txiki.js), eliminating the need for a local HTTP server and its associated security surface.

Zero compilation – Applications are written in plain JavaScript, CSS, and HTML. No build step is required unless the developer opts into a framework like Vite, React, Vue, or Svelte.

System integrations – Secure credential storage, SQLite databases, and automatic updates are supported natively.

Website wrapping – Pointing the WebView at a URL turns any web site into a desktop app instantly.

Development Workflow

Project scaffolding

tinyjs new appname

This generates a minimal project structure. Two key files: main.js – “backend” code that exposes services to the frontend. It can perform system operations that browser JavaScript cannot.

Frontend files (HTML/CSS/JS) – standard web UI.

Backend API example

export const api: Record<string, TinyApiHandler> = {
  hello: async ({ name }: { name: string }) => 'hi ' + name + ' — from the backend',
};

Frontend consumption

await tiny.api.call('hello', { name: 'World' });

Running with hot module replacement

tinyjs dev

Example Applications (App Store)

Stroh-Spijer ships a built-in app store containing 25 free demo applications, all running entirely on the desktop:

World Clock – 3.8 MB ZIP

Clipboard History – 3.7 MB

Markdown Editor – 4.9 MB

Desktop Mascot – 3.8 MB

SQLite Browser – 4.1 MB

Winamp Clone – 7.4 MB

Early testers report some macOS-originated apps exhibit bugs on Windows, which is expected for a young cross-platform project.

Benefits and Limitations

Fast startup – tiny binaries load almost instantly.

Low resource usage – reduced memory footprint and, theoretically, lower laptop battery drain.

Cross-platform visual variance – because each OS renders with its own WebView, pixel-perfect consistency is not guaranteed.

Maturity – the ecosystem is nascent; some rough edges remain.

TinyJS demonstrates that even on modern powerful hardware, there is still strong demand for lightweight, resource-efficient desktop tools — a philosophy reminiscent of 1990s software craftsmanship.