A pure Kotlin, UI framework for the Web

kotlin, kotlin-js, object-oriented, webapp



A pure Kotlin, UI framework for the Web

Kotlin 1.3.72 License: MIT

Why Doodle?


Doodle is written entirely in Kotlin and so are its apps. Doodle Applications do not use HTML, CSS styles or Javascript libraries. In fact, apps are not aware of the Browser (or Browser concepts) at all, and can be written entirely as common (cross-platform) code in multi-platform setups.


Creating expressive, intuitive apps is natural with Doodle. It makes complex rendering easy with powerful, vector-oriented rendering, provides fully customizable layouts and simplifies pointer and keyboard handling.

Simply define your View hierarchy, business logic and go.

Vector Oriented

It is easy to build beautifully detailed UIs with Doodle. All rendering in Doodle is vector-oriented; so ellipses, paths, lines, gradients, affine transforms etc. are as simple to use as images and rectangles.


Doodle gives you control over all aspects of the UI presentation, including pixel-level positioning, making it easier to precisely control rendering.


Doodle has several libraries and a collection of modules. This allows selective adoption of various features and helps with bundle size. Apps written with Doodle are also dependency-injected; and there are no global objects or state to make mocking challenging.

Hello World

class HelloWorld(display: Display): Application {
    init {
        display.children += object: View() {
            init { size = display.size }

            override fun render(canvas: Canvas) {
                canvas.text("Hello, world!",
                    at = Origin, 
                    brush = ColorBrush(Black))

    override fun shutdown() {}

fun main() {
    application {
        HelloWorld(display = instance())


Doodle is still under active development, so there are going to be gaps and bugs. Please report issues, and submit feature requests.