3. README.md — Professional (Google-grade)

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<!-- NEXUS W3C VALIDATOR -->
<!-- Multi-Standard Code Validator for the Web -->
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# 🌐 NEXUS W3C VALIDATOR

**The multi-standard code validator that runs on your machine.**

**8 W3C standards. 1 localhost server. 0 dependencies.**

[Quick Start](#-quick-start) · [Features](#-features) · [API](#-api-reference) · [Standards](#-w3c-standards-supported) · [Documentation](#-documentation)

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---

## 📖 **Overview**

**NEXUS W3C Validator** is a professional-grade, single-file code validator that integrates **8 official W3C standards** into one unified local server. Built for developers, auditors, and CI/CD pipelines who demand **precision, speed, and privacy**.

Unlike cloud-based validators, NEXUS runs **entirely on your machine** — no data leaves your system, no API keys, no rate limits, no telemetry.

```bash
git clone https://github.com/Aissamohammedi88/nexus-w3c-validator
cd nexus-w3c-validator
python3 nexus_w3c_validator.py
# → http://localhost:8888/

---

✨ Features

🎯 8 W3C Standards Integrated

Standard Purpose

1 📄 Nu HTML Checker Validate HTML5 documents 2 🎨 CSS Validator Validate CSS stylesheets 3 🔗 Link Checker Detect broken links 4 🧬 RDF Validator Validate RDF/OWL/Turtle 5 🌍 i18n Checker Internationalization compliance 6 📚 EPUBCheck EPUB publication validation 7 📡 Feed Validator RSS and Atom feeds 8 🧪 Web Platform Tests Web interop testing

⚡ Performance & Design

· Zero dependencies — pure Python standard library · Single file — one script runs everything · Localhost-only — full privacy, no cloud · Auto-detection — analyze any code type automatically · Multi-format output — JSON, HTML, human-readable · REST API — integrate with any tool · Web dashboard — modern cyberpunk UI · Real-time stats — track validations

🔒 Privacy First

· No data leaves your machine · No telemetry · No API keys required · No rate limits · Open source (NEXUS-OPEN-2.0)

---

🚀 Quick Start

Requirements

· Python 3.9+ (any OS: Linux, macOS, Windows) · No external dependencies

Installation

# Clone
git clone https://github.com/Aissamohammedi88/nexus-w3c-validator.git
cd nexus-w3c-validator

# Make executable (Linux/macOS)
chmod +x nexus_w3c_validator.py

# Run
python3 nexus_w3c_validator.py

Access the Dashboard

Open your browser:

http://localhost:8888/

Custom Port

python3 nexus_w3c_validator.py --port 9999

Headless Mode (no browser)

python3 nexus_w3c_validator.py --no-browser

---

🐧 Command Line Usage

# Default port (8888)
python3 nexus_w3c_validator.py

# Custom port
python3 nexus_w3c_validator.py --port 8080

# Server only (no browser auto-open)
python3 nexus_w3c_validator.py --no-browser

# Help
python3 nexus_w3c_validator.py --help

---

📡 API Reference

GET Endpoints

Endpoint Description GET / Web dashboard (HTML) GET /api/validators List of available validators GET /api/health Health check GET /api/docs Full API documentation

POST Endpoints

Endpoint Description Body POST /api/validate/auto Auto-detect + validate {"content": "..."} POST /api/validate/html HTML5 validation {"content": "..."} POST /api/validate/css CSS validation {"content": "..."} POST /api/validate/i18n i18n check {"content": "..."} POST /api/validate/feed RSS/Atom validation {"content": "..."} POST /api/validate/rdf RDF validation {"content": "..."} POST /api/validate/full Full validation {"content": "..."}

Examples

Validate HTML:

curl -X POST http://localhost:8888/api/validate/html \
-H "Content-Type: application/json" \
-d '{"content": "<!DOCTYPE html><html lang=\"fr\"><head><title>Test</title></head><body><h1>Hello</h1></body></html>"}'

Auto-detect:

curl -X POST http://localhost:8888/api/validate/auto \
-H "Content-Type: application/json" \
-d '{"content": "body { color: red; }"}'

Response example:

{
"auto_detected": "css",
"validation": {
"valid": true,
"errors": [],
"warnings": [],
"count_errors": 0,
"count_warnings": 0
},
"duration_ms": 0.42,
"hash": "a3f5e9d2c...",
"size": 19
}

---

🌐 W3C Standards Supported

📄 1. Nu HTML Checker

Validates HTML5 documents for:

· Missing DOCTYPE · Unclosed tags · Duplicate attributes · Missing alt attributes · Empty links · Charset declaration · Accessibility basics

Official: validator.w3.org/nu

---

🎨 2. CSS Validator

Validates CSS stylesheets for:

· Balanced braces · Balanced parentheses · Missing semicolons · Empty rules · Syntax errors

Official: jigsaw.w3.org/css-validator

---

🔗 3. Link Checker

Detects broken links in:

· · · · <script src="...">

Official: validator.w3.org/checklink

---

🧬 4. RDF Validator

Validates RDF documents in:

· RDF/XML · Turtle · N3 · JSON-LD · OWL

Official: w3.org/RDF/Validator

---

🌍 5. i18n Checker

Validates internationalization:

· lang attribute · dir attribute · Charset (UTF-8) · Control characters · Non-ASCII class names · Non-NFC identifiers

Official: validator.w3.org/i18n-checker

---

📚 6. EPUBCheck

Validates EPUB publications:

· EPUB 2 and 3 · OPF, NAV, NCX · Conformance levels

Official: validator.w3.org/epub-checker

---

📡 7. Feed Validator

Validates feeds:

· RSS 0.91, 0.92, 1.0, 2.0 · Atom 0.3, 1.0 · iTunes, Podcast feeds

Official: validator.w3.org/feed

---

🧪 8. Web Platform Tests

Web interoperability testing:

· DOM APIs · CSS · HTML · JavaScript · Web APIs

Official: wpt.fyi

---

🏗️ Architecture

nexus_w3c_validator.py
├── HTTP Server (ThreadingHTTPServer)
├── NexusValidator (Orchestrator)
│ ├── HTMLValidator
│ ├── CSSValidator
│ ├── I18nChecker
│ ├── FeedValidator
│ └── RDFValidator
├── REST API Handler
├── Web Dashboard (HTML/CSS/JS)
└── Stats Engine

No external dependencies. Pure Python standard library.

---

💡 Use Cases

👨‍💻 For Developers

· Validate code before commit · CI/CD integration · Pre-deployment checks · Learning web standards

🔍 For Auditors

· Security audits · Accessibility audits · i18n compliance · Multi-site scanning

🏢 For Enterprises

· Local validation (no cloud) · Private codebase audit · Air-gapped environments · Compliance reporting

---

📊 Dashboard Preview

The web dashboard includes:

· 🎯 Auto-detect tab — paste anything · 📄 HTML tab — HTML5 validation · 🎨 CSS tab — stylesheet validation · 🌍 i18n tab — internationalization · 📡 Feed tab — RSS/Atom validation · 🧬 RDF tab — RDF validation · ✅ Full tab — complete analysis

Cyberpunk UI with:

· Dark background (#0a0a0f) · Gold accent (#c8a45c) · Cyan highlights (#00d4ff) · Real-time stats · JSON output

---

🔐 Security & Privacy

Aspect Guarantee Data locality 100% localhost — no cloud Telemetry Zero API keys Not required Rate limits None Code leaks Impossible Sandbox Local file only Open source Full transparency

---

🧪 Testing

Run a quick self-test:

# Health check
curl http://localhost:8888/api/health

# List validators
curl http://localhost:8888/api/validators

# Test HTML
curl -X POST http://localhost:8888/api/validate/html \
-H "Content-Type: application/json" \
-d '{"content": "<!DOCTYPE html><html><head><title>T</title></head><body></body></html>"}'

---

📁 Project Structure

nexus-w3c-validator/
├── nexus_w3c_validator.py # Single-file server
├── README.md # This file
├── LICENSE # NEXUS-OPEN-2.0
├── .gitignore # Git ignore rules
├── assets/ # Screenshots / logos
│ ├── preview.png
│ └── dashboard.png
└── docs/ # Documentation
├── API.md
├── STANDARDS.md
└── CONTRIBUTING.md

---

🤝 Contributing

We welcome contributions from the community:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

See CONTRIBUTING.md for details.

---

📜 License

NEXUS-OPEN-2.0 — Free for personal and commercial use.

· ✅ Use commercially · ✅ Modify · ✅ Distribute · ✅ Private use · ❌ No warranty · ❌ No liability

See LICENSE file for details.

---

👤 Author

Aissa Mohammedi (DGK) Founder & Chief Systems Architect — Nexus Ecosystem

· 📧 Email : awamomo646@outlook.com · 💼 LinkedIn : aissa-mohammedi · 🐙 GitHub : Aissamohammedi88

---

🌟 Acknowledgments

· W3C for the standards and open-source validators · Open Source Community for inspiration · Mesut.uk for the design aesthetic · You for using NEXUS

---

🌐 Built with precision. Validated with standards. Delivered with pride.

NEXUS W3C VALIDATOR — v1.0.0

Aissa Mohammedi (DGK) · Québec · 2026

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