Hephaestus

Colour · critique · a buildable library

A design forge
that shows its work.

Hephaestus turns a plain-language brief into a working palette, tells you which of its rules the palette breaks and why, and keeps a library of 1,750 design directions you can build from rather than admire. Every answer comes from its own arithmetic — nothing is generated for you by a model, so the same brief gives the same answer tomorrow, and you can look up how it was reached.

Desktop · Windows, macOS and Linux · free, forever, no account

Download Hephaestus

§ 01 — downloads

Direct, stand-alone installers for Windows, macOS, and Linux. Built from source, 100% offline and local-first.

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macOS Installation Note: Because Hephaestus is an independent, community-driven project without commercial Apple notarization fees, macOS Gatekeeper may show a developer prompt on the very first launch. To open: Right-click the app in Finder → select Open → click Open once. Subsequent launches open instantly and normally.
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What Hephaestus Delivers

§ 02 — capabilities

A complete suite for visual web design, color science, design systems, and real-time accessibility auditing.

▢

Studio Canvas visual builder

A freeform design surface with drag-and-drop blocks. Select, resize, reposition, and reorder elements with pixel precision.

  • Pre-built section templates: Hero, Bento Grid, Pricing, Features, FAQ
  • Responsive viewport preview: Desktop (1200px), Tablet (820px), Mobile (400px)
  • Single-page and multi-page site navigation modes
✦

Akmon Forge perceptual color

Generate coherent, accessible color palettes directly in the human-perceptual OKLCH color space instead of sRGB or HSL.

  • Calculates exact WCAG 2.2 AA & AAA contrast ratios
  • Simulates color-blindness (Deuteranopia, Protanopia, Tritanopia)
  • Lock favorite swatches and re-harmonize remaining roles in 1 click
⚙

Cedalion Critic design intelligence

Your interactive built-in design critic. It continuously inspects your layout and palette to spot weaknesses and suggest actionable solutions.

  • Scores visual hierarchy, spacing discipline, and readability
  • Provides 1-click automatic contrast and neutral tint fixes
  • 100% built-in and offline — zero telemetry, zero external APIs
⇪

Production Export clean code

No walled gardens or proprietary binary blobs. Every design you create exports instantly into production-ready web code.

  • Clean, lightweight, standalone static HTML & CSS
  • Tailwind CSS JSX components ready to paste into React/Next.js
  • Design tokens: CSS custom properties, SCSS variables, JSON tokens
☰

Design Directions 1,700+ recipes

An extensive, curated library of layout and typography systems reflecting modern web design directions.

  • Curated typography scales: Minor Third (1.2), Major Third (1.25), Perfect Fourth (1.333)
  • Systematic 4px/8px spacing rhythms and elevation tokens
  • Tested component recipes for high-converting SaaS, tools, and portfolios
🔒

Local-First private & fast

Built with Tauri v2 and Rust. Hephaestus runs entirely on your local hardware with negligible RAM overhead and zero telemetry.

  • Zero accounts, zero tracking, zero mandatory cloud logins
  • Ultra-light memory usage (< 50 MB RAM typical)
  • 100% offline capability — design anywhere without an internet connection

Technical Specifications

§ 03 — system & standards

Engineered for high performance, accessibility compliance, and developer transparency.

Application Core
Tauri v2 + Rust + React 19
Color Space
OKLCH / OKLab (Perceptual Uniformity)
Accessibility Standards
WCAG 2.2 Level AA & AAA
CVD Simulation
Brettel / Viénot LMS Matrix
Code Exports
HTML5, Modern CSS, Tailwind CSS, JSON
Operating Systems
Windows 10/11, macOS 11+, Linux
Telemetry & Tracking
None (0 analytics, 100% local)
Licence
MIT Open Source