High-performance JSX UI outside the browser, with native rendering, standard Vue Vapor and Solid support, a Tailwind design system, and 60 FPS animation under an 8 MB memory budget.
PocketJS keeps the authoring model modern while moving the expensive work to build time and to a tiny Rust core. The result is a real interface stack that can run smoothly on a Sony PSP.
Layout runs in the Rust core through taffy, so a familiar flex-col gap-4 interface lays out deterministically on PSP, browser and Bun.
Class literals become compact style records at build time. There is no CSS parser, stylesheet cascade or utility runtime on the device.
Inter glyphs are baked into coverage atlases and rendered with sub-pixel positioning, so tiny PSP screens still get readable UI text.
Write Solid or Vue Vapor components with their own reactivity APIs, run them on QuickJS, and let PocketJS handle the native pixels.
import { Text, View } from "@pocketjs/framework/components";
import { createSignal } from "solid-js";
export default function Counter() {
const [n, setN] = createSignal(0);
return (
<View class="flex-col items-center gap-4 p-6 bg-slate-950">
<Text class="text-2xl text-slate-50 font-bold">Count: {n()}</Text>
<View class="px-4 py-2 rounded-xl bg-slate-700 focus:bg-slate-500" focusable onPress={() => setN(n() + 1)}>
<Text class="text-base text-slate-50 font-bold">Press Circle</Text>
</View>
</View>
);
}import { Text, View } from "@pocketjs/framework/vue-vapor/components";
import { ref } from "vue";
export default function Counter() {
const n = ref(0);
return (
<View class="flex-col items-center gap-4 p-6 bg-slate-950">
<Text class="text-2xl text-slate-50 font-bold">Count: {n.value}</Text>
<View class="px-4 py-2 rounded-xl bg-slate-700 focus:bg-slate-500" focusable onPress={() => n.value++}>
<Text class="text-base text-slate-50 font-bold">Press Circle</Text>
</View>
</View>
);
}Complete open-source apps running on real handhelds — not tech demos.
A Counter-Strike-shaped FPS that plays the classic GoldSrc-era maps — BSP world, lightmaps, bots, recoil, round flow. The HUD is a Solid app; the round rules and weapon tables are TypeScript. It holds a locked 60 FPS on a 333 MHz PSP and ships as one file you drop on a Memory Stick.
A real Figma Community file, open on a PSP: the Paper Wireframe Kit — 14,430 nodes, 2,293 component instances, a canvas 26,000 pixels wide. The cooker bakes it into streaming tiles, so the device never parses the file. Pan with the analog nub, zoom with the shoulders — and the same bundle runs at native 960×544 on PS Vita.
YouTube on a PSP, where the network is a USB cable: a Mac companion runs yt-dlp and ffmpeg, and the handheld plays a ring buffer that happens to be a file. Search with the system keyboard, browse rows with CJK titles the device could never typeset, and watch at 12 fps with 44.1 kHz audio — pause, seek and all — while the UI never drops from 60 FPS.
You keep JSX and signals. Everything expensive becomes native data, native draw calls — and a testable machine.
A virtual clock makes every frame a pure function of the input tape. Golden tests compare whole framebuffers, byte for byte — the same on CI, desktop and hardware. Scrub backwards, replay any session, on a real PSP.
Tailwind literals become numeric style records at build time. No parser, no cascade, no utility runtime on the device.
taffy 0.11 lays out in the Rust core — identical positions on every target, provable in goldens.
Coverage atlases with sub-pixel positioning. Runtime text is compositing, not font rasterization.
Tweens, springs and keyframe timelines tick in Rust at a fixed 1/60 s. JS declares; the core animates.
D-pad focus, analog nub, touch, a virtual cursor — and a system on-screen keyboard any app can summon with one call.
Every session records itself. Step to any frame, inspect the native tree, diff against a golden — over USB to real hardware.
Pocket3D runs BSP worlds with PVS through sceGu on PSP and wgpu on desktop — OpenStrike holds a locked 60 FPS with a Solid HUD on top.
The no_std core needs a framebuffer and a few buttons; a pocket.json contract decides where a bundle may ship.
Bring modern frontend ergonomics to hardware that was never built for the web.