Hyperion Docs

Developer-first documentation stack with diagrams-as-code

A two-service monorepo combining Fumadocs v15 (Next.js) for beautiful MDX documentation with Kroki for rendering diagrams from code. Built for developer experience with one-command setup and hot reload in Docker.

Features

• 🎨 Dark/Light Theme Support - All diagrams adapt automatically
• 🔍 Zoomable Diagrams - Click any diagram to open in fullscreen with pan/zoom
• 🚀 Hot Reload - Edit MDX or components, see changes instantly
• 🔒 Secure by Default - Path traversal protection, size limits, language allowlist
• 📦 One Command - pnpm dev starts docs locally (cross-platform)
• 🎯 Type-Safe - TypeScript strict mode throughout

Tech Stack

• Node.js 22 with pnpm
• Next.js 15 App Router
• Fumadocs v15 for documentation UI
• Kroki for diagram rendering
• Mermaid for inline diagrams
• React Flow for zoomable viewer
• TailwindCSS 3 for styling
• Docker & Docker Compose for containerization

Quick Start

Prerequisites

• Node.js 22+
• pnpm 9+

Installation

# Clone the repository
git clone https://github.com/wallwhite/hyperion-docs.git

# Navigate to the project directory
cd hyperion-docs

# Install dependencies
pnpm install

# Start docs locally (no Docker)
pnpm dev

Visit http://localhost:3000 - changes hot-reload automatically!

If you want Docker-based development instead:

pnpm dev:docker

Stop Services

# Stop Docker-based dev services
pnpm stop

Project Structure

hyperion-docs/
├── apps/
│   └── docs/                    # Next.js + Fumadocs app
│       ├── app/                 # Next.js App Router
│       │   ├── api/diagram/     # Diagram proxy API
│       │   ├── docs/            # Docs routes
│       │   ├── layout.tsx       # Root layout
│       │   └── page.tsx         # Home page
│       ├── components/          # React components
│       ├── content/docs/        # MDX documentation
│       ├── diagrams/            # Diagram source files (.puml, .dot)
│       ├── openapi/             # OpenAPI schema files (.yaml)
│       ├── lib/                 # Utilities
│       ├── mdx-components.tsx   # MDX component config
│       ├── source.config.ts     # Fumadocs source config
│       └── Dockerfile           # Docs service Dockerfile
├── docker-compose.yml           # Services orchestration
├── pnpm-workspace.yaml          # Monorepo config
└── package.json                 # Root scripts

Usage

Inline Mermaid Diagrams

<Diagram lang="mermaid" chart="
graph TD;
  A[Client] --> B[Server];
  B --> C[Database];" />

External Diagrams (PlantUML, Graphviz, etc.)

Place your diagram files in apps/docs/diagrams/:

<Diagram lang="plantuml" path="erd.puml" alt="Entity Relationship Diagram" />
<Diagram lang="graphviz" path="flow.dot" alt="Processing Flow" />

Supported Languages

• PlantUML - puml, plantuml
• Graphviz - dot, graphviz
• Mermaid - mermaid (or use <Mermaid> component)
• C4 PlantUML - c4plantuml

Easily extend by adding to LANG_MAP in apps/docs/app/api/diagram/route.ts.

Architecture

Flow

MDX File → <Diagram> Component → /api/diagram API Route → Kroki Service → SVG/PNG Response

API Route (/api/diagram)

• Runtime: nodejs (required for fs access)
• Security: Path allowlist, size limits, language validation
• Caching: Cache-Control: no-store in dev

Query Parameters:

• lang - Diagram language (e.g., puml, dot)
• path - Relative path to diagram file
• fmt - Output format (svg or png, default: svg)

Components

<Diagram>

• Fetches from /api/diagram or generates Mermaid diagrams directly from the chart string
• Opens modal on click
• Supports SVG

<PreviewModal>

• Whiteboard canvas
• Pan, zoom, reset controls

Development

Local Development (without Docker)

pnpm install
pnpm dev

Note: Diagram rendering uses KROKI_BASE_URL when set. By default, it uses https://kroki.io.

Docker Development (optional)

pnpm dev:docker
pnpm stop:docker

Adding New Diagram Types

1. Add language mapping to apps/docs/app/api/diagram/route.ts:

   const LANG_MAP: Record<string, string> = {
     // ...existing
     d2: 'd2',  // Add new type
   };

2. Create diagram files in apps/docs/diagrams/

3. Use in MDX:

   <Diagram lang="d2" path="my-diagram.d2" />

Customizing Styles

Edit apps/docs/tailwind.config.ts to customize Tailwind or override Fumadocs styles.

Security

• Path Traversal: All paths resolved relative to apps/docs/diagrams and validated
• File Size: Max 256 KB per diagram file
• Language Allowlist: Only mapped languages accepted
• No Code Execution: Diagrams treated as opaque text sent to Kroki

Troubleshooting

Diagrams not rendering

1. Check Kroki is running
2. Verify diagram file path is relative to apps/docs/diagrams
3. Check browser console for API errors
4. Confirm language is in LANG_MAP

TypeScript errors

cd apps/docs
pnpm typecheck

License

MIT

Contributing

1. Fork the repo
2. Create a feature branch
3. Make your changes
4. Submit a pull request

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Built with ❤️ using Fumadocs, Next.js, and Kroki