VanJS: A 0.9kB Grab 'n Go Reactive UI Framework without React/JSX

📣 VanJS 1.0.0 is here →

Enable everyone to build useful UI apps with a few lines of code, anywhere, any time, on any device.

VanJS (abbreviated Vanilla JavaScript) is an ultra-lightweight, zero-dependency, and unopinionated Reactive UI framework based on pure vanilla JavaScript and DOM. Programming with VanJS feels like building React apps in a scripting language, without JSX. Check-out the Hello World code below:

// Reusable components can be just pure vanilla JavaScript functions.
// Here we capitalize the first letter to follow React conventions.
const Hello = () => div(
    li(a({href: ""}, "🍦VanJS")),

van.add(document.body, Hello())
// Alternatively, you can write:
// document.body.appendChild(Hello())

Try on jsfiddle

You can convert any HTML or MD snippet into VanJS code with our online converter.

VanJS helps you manage states and UI bindings as well, with a more natural API:

const Counter = () => {
  const counter = van.state(0)
  return span(
    "❤️ ", counter, " ",
    button({onclick: () => ++counter.val}, "👍"),
    button({onclick: () => --counter.val}, "👎"),

van.add(document.body, Counter())


Try on jsfiddle

Why VanJS?

Reactive Programming without React/JSX

Declarative DOM tree composition, reusable components, reactive state binding - VanJS offers every good aspect that React does, but without the need of React, JSX, transpiling, virtual DOM, or any hidden logic. Everything is built with simple JavaScript functions and DOM.

Grab 'n Go

No installation, no configuration, no dependencies, no transpiling, no IDE setups. Adding a line to your script or HTML file is all you need to start coding. And any code with VanJS can be pasted and executed directly in your browser's developer console. VanJS allows you to focus on the business logic of your application, rather than getting bogged down in frameworks and tools.


VanJS is a very thin layer on top of Vanilla JavaScript and DOM, barely enough to make the DOM manipulation and state binding as ergonomic as (if not more than) React, and it delegates most of work to standard browser APIs implemented in native code. As a result, the minified bundled size of VanJS is just 1.7kB (0.9kB gzipped), which is 50~100 times smaller than most popular UI frameworks, making it the smallest reactive UI framework in the world:

.min.js.gz .min.js

Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.

-- Antoine de Saint-Exupéry, Airman's Odyssey

Easy to Learn

Simplicity at its core. 5 major functions (van.tags, van.add, van.state, van.derive, van.hydrate) + 4 auxiliary functions (van.tagsNS, van._, van.val, van.oldVal). The the entire tutorial plus the API reference is just one single web page, and can be learned within 1 hour for most developers.


VanJS is among the fastest web frameworks, according to the results by krausest/js-framework-benchmark. For SSR, Mini-Van is 1.75X to 2X more efficient compared to React.

TypeScript Support

VanJS provides first-class support for TypeScript. Simply download the corresponding .d.ts file along with your .js file, and you'll be able to take advantage of type-checking, IntelliSense, large-scale refactoring provided by your preferred development environment. Refer to the Download Table to find the right .d.ts file to work with.

Want to Learn More?

Source Code

Support & Feedback

🙏 VanJS aims to build a better world by reducing the entry barrier for UI programming, with no intention or plan on commercialization whatsoever. If you find VanJS interesting, or could be useful for you some day, please consider starring the project on GitHub. It takes just a few seconds but your support means the world to us and helps spread VanJS to a wider audience.

Star Watch Discuss Issue Follow @vanjs-org

In the name of Vanilla of the House JavaScript, the First of its name, Smallest Reactive UI Framework, 0.9kB JSX-free Grab 'n Go Library, Scripting Language for GUI, ChatGPT-Empowered Toolkit, by the word of Tao of the House Xin, Founder and Maintainer of VanJS, I do hereby grant you the permission of VanJS under MIT License.

Contact us: Twitter@taoxin / Tao Xin / / LinkedInTao Xin