Native UIs at the density of Tailwind, the quality of Flutter.

Vel is a declarative UI language with a reactive core, a from-scratch GPU renderer, and first-class C/C++ interop. Write 2.33× fewer tokens than React — ship a real native binary.

$ curl -fsSL https://vel.kadarla.com/install.sh | bash

Get started in 15 min Try the playground →

users.vel vel

 use "backend/users.h"

#UserList
  @users: std::vector<User> = await fetchUsers()
  @filter = ""

  V g=md p=lg
    In placeholder="Search…" value=$filter
    if $users.size() &gt; 0
      List of=$users as=u
        Card -> click => open(u.id)
          H g=sm
            Avatar src=$u.avatar
            V
              T $u.name font=bold
              T $u.email fg=fgMuted
    else
      Spinner

velc · compiles to ↓

main.cpp C++

 #include "vel/App.h"
#include "users.vel.h"

int main() {
  vel::App app(900, 640, "Demo");
  app.setRoot(std::make_unique<UserList>());
  return app.run();
}

2.33×

fewer tokens than React + Tailwind

vel bench token

~93×

faster warm relayout (10k rows)

vel bench layout

~1 ms

per-frame CPU, p50 (showcase)

VEL_PERF=60

CPU when idle — damage-tracked

glfwWaitEvents

Three strictly-layered tiers

Registry → Framework → Engine

One-way dependencies, never the reverse. Each tier is independently useful — and the engine, Lume, stands on its own.

Tier 2 →

Registry

Opinionated, beautiful-by-default components — Btn, Card, Table, Tabs, Dialog, Chart. shadcn-grade UI in one-token names.

BtnCardTableTabsDialogChartToasterTreeView

Tier 1 →

Framework

The reactive substrate. Signals, Computed, AsyncSignal, layout, router, net, storage — ~0 CPU when idle via damage tracking.

SignalComputedAsyncSignalRouterFlex / GridNet / Io

Tier -1 →

Lume Engine

A from-scratch GPU 2D renderer on Dawn/WebGPU. Analytic SDF shapes, FreeType glyph atlas, one source → Metal, D3D12, Vulkan, browser.

Dawn / WebGPUSDF shapesGlyph atlasMetal · D3D12 · Web

Why teams pick Vel

⚡

Compiles to native

velc emits idiomatic C++ that links into libvel. No VM, no JS bridge, no Electron. Just a native binary.

🎨

Beautiful by default

Every primitive renders well with zero config. Theme tokens (bg2, accent, md) are the language of styling.

🔁

Reactive substrate

Signals, Computed and AsyncSignal drive rebuilds. State, scroll, focus and drag survive hot reload.

🧩

First-class C/C++ interop

use "header.h" and call your backend directly. The framework knows nothing about your data layer.

🌐

One source, everywhere

macOS, Windows and the browser render identically — native WebGPU via WebAssembly.

♿

Accessible on the web

A live DOM mirror gives screen readers, keyboard nav, IME and focus rings. Honors reduced-motion.

Build a real app today.

Install, scaffold, and see a native window in under 15 minutes — or edit Vel live in your browser right now.

$ curl -fsSL https://vel.kadarla.com/install.sh | bash

Install Vel Open playground