Kinetica

Kinetica is a Kotlin UI framework built around one idea: the UI is a value. Every render produces an immutable, serializable Node tree. Because the tree is a value, you get things most frameworks bolt on afterwards, for free and by construction: headless testing, HTML server rendering, streaming server components, an execution journal with time-travel replay, and a retained DOM renderer that patches by diffing values.

It is "React without the historical constraints": one UI loop, synchronous atomic commits, a single reactive cell primitive, explicit effects, and linear causality you can read back from the journal — no fibers, no lanes, no concurrent rendering.

@UiComponent
fun ComponentScope.Counter() {
    var count by state { 0 }
    val label by derived { "Clicked $count times" }

    column {
        text(label)
        button(onClick = event { count += 1 }) {
            text("Increment")
        }
    }
}

fun main() {
    mountKineticaApp("#app") { Counter() }
}

Design pillars

• Node is a serializable value. Trees can be asserted in tests, snapshotted, sent over the wire as server components, and diffed for minimal DOM patches.
• One UI loop, atomic commit. An event runs, cells update, one render commits synchronously. No tearing, no partially applied states, no scheduling heuristics to debug.
• One reactive primitive. state, derived and store are all cells with dependency tracking, and resources cache through the same machinery. Effects are explicit (watch, launchEffect) — no auto-tracking surprises.
• Linear causality. The runtime journals every event, cell write, render cause and effect. replay() reconstructs state at any point. Debuggability outranks features.
• Batteries included. Router, forms, motion, data/offline, persistence, theming, markdown and a test harness are first-party modules with the same conventions.

Where things run

Reading order

Start with Getting started, then the Core section in order: State & reactivity, UI DSL, Lists & keys, Effects, Resources. The Batteries section covers the first-party modules. If you want to know how the renderer stays fast, read Browser renderer and Performance.

This site is dogfood: every page is Markdown parsed by kinetica-markdown, rendered to a Kinetica Node tree on the JVM, and serialized with the same toSafeHtml() that powers server components. The interactive widgets are Kinetica browser apps mounted into the page.