v1.0 · Public beta

Ship distinctive interfaces, never homogenized output.

Void Energy is a runtime theming engine and AI-constraint architecture for Svelte 5. One codebase ships any number of brands, switchable at runtime — and AI-generated code stays on-brand by construction.

Read the docs

Trusted by teams at

NORTHWINDAPERTUREINITECHWONKA LABSHOOLIPIED PIPERSTARK INDUSTRIESCYBERDYNE

Features

Built for the AI-generation era

A constraint architecture that keeps AI output on-brand, accessible, and multi-tenant — without rot.

Three-layer enforcement

L0 framework-agnostic preset, L1 Svelte design system, L2 AI rule layer. AI generation passes durability gates by construction.

tokens · components · rules

Runtime theming engine

One codebase ships any number of brands. Atmosphere × physics × mode × brand identity, switchable at runtime with no rebuild.

glass · flat · retro

AI-native by design

Token registry, component registry, and rule walk-up make AI agents compose against the system instead of around it.

registry · rules · exemplars

Architecture

Three layers, one outcome

From token authorship to AI-generated output — every layer enforces the next.

Author tokens

Define an atmosphere — palette, physics, motion, brand identity — in 30 lines of TypeScript. The generator emits SCSS variables, Tailwind theme entries, and a JSON registry from one source.
```
// src/config/atmospheres.ts
export const frost: AtmosphereDefinition = {
  id: 'frost',
  energy: '#a4d8ff',
  physics: 'glass',
  mode: 'dark',
};
```
Compose primitives

Pages compose 44 shipped UI primitives that already carry physics, accessibility, and atmosphere reactivity. Native HTML where the browser already does it; custom widgets only where no native exists.
```
<FormField label="Email">
  {#snippet children({ fieldId })}
    <input id={fieldId} type="email" bind:value={email} />
  {/snippet}
</FormField>
```
Generate under constraint

AI agents read a registry, exemplars, and rules at the top of every task. Output passes the same gates as human code — registry check, type check, lint, design-md verify — by construction.
```
npm run check
  ↳ check:registry
  ↳ svelte-check
  ↳ lint:design-md
  ↳ check:skill
```

By the numbers

What three layers of enforcement produce

The constraint architecture, expressed quantitatively.

Shipped UI primitives

WCAG AA pass rate on default chrome

Tokenized motion + surface variables per physics

Customers

Trusted by teams building flagship interfaces

Builders shipping multi-brand surfaces under real AI-generation load.

We replaced four design tokens, a Tailwind config, and a homegrown theming layer with one atmosphere file. Switched two acquired brands over in a weekend.

Sarah Chen Staff Engineer · Northwind Labs

Our AI-generated PRs used to look generic-SaaS. Void Energy is the first system where the constraints are legible enough that the agents actually compose with the design language instead of around it.

Theo Ostrowski Head of Design Engineering · Aperture

Plans

Simple pricing, no per-atmosphere fees

Pick a tier; ship every brand from one codebase. No seat limits on atmospheres or themes — only on contributors.

Free

$0 forever

For personal projects and prototypes.

Full L0 + L1 design system
Unlimited atmospheres
Community Discord support
MIT license

Get started

Pro Most popular

$24 per seat / month

For teams shipping multi-brand interfaces.

Everything in Free
Premium ambient layers + kinetic text
AI-generation analytics
Priority email support
Brand profile templates

Start free trial

Enterprise

Custom annual contract

For organizations with multi-tenant requirements.

Everything in Pro
Dedicated success engineer
On-prem deployment + SLA
Custom atmosphere authoring
SOC2 / HIPAA

Contact sales

View full pricing →

Questions

Frequently asked

The questions teams ask before adopting Void Energy.

Does it work with React or Vue?

The framework-agnostic L0 preset (Tailwind + vanilla JS) ships as a separate package and runs anywhere CSS does. The full L1 design system requires Svelte 5.

How does AI generation stay on-brand?

Three layers: tokens constrain vocabulary, the component registry constrains primitives, and the .claude/rules/ files constrain composition. AI-generated PRs pass the same gates as human ones.

Can I ship multiple brands from one codebase?

Yes. The brand profile axis carries identity (radii, motion, typography, weights, fonts) as sparse token overlays. Atmospheres swap at runtime; brands swap at runtime; both compose with physics and mode.

What's the lift to add a new theme?

An atmosphere is a 30-line file in src/config/atmospheres.ts. Run npm run build:tokens; the engine picks it up. AI-generated atmospheres validate against the same schema.

Is it accessible by default?

Native HTML primitives carry browser-owned a11y; ARIA + data-state is the state contract; reduced-motion and high-contrast are first-class. Every shipped primitive passes WCAG AA at default chrome.

Start composing under constraints

Read the AI playbook, browse the registry, and ship your first page in under an hour.

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