Networking Toolbox is a self-hosted, offline-first web application designed for sysadmins and network engineers who need quick access to essential networking tools without relying on internet connectivity. Built with Svelte and SvelteKit, it bundles over 100 utilities for network conversion, calculation, diagnostics, and configuration verification—all running entirely in the browser. The tool addresses the common pain point of being unable to access online resources during network outages, air-gapped environments, or secure internal operations. It’s ideal for field technicians, DevOps teams managing infrastructure in restricted environments, and anyone who needs reliable, on-demand network diagnostics without external dependencies.
The app is designed for deployment flexibility: it can be run via Docker, hosted statically on GitHub Pages or any CDN, deployed to Vercel/Netlify, or served via a Node.js server. Its zero third-party dependency architecture ensures security and reliability in high-sensitivity environments where external services are prohibited.
What You Get
- 100+ offline networking utilities - Includes tools for IP subnetting, CIDR calculations, port scanning reference tables, DNS record converters, MAC address validators, and protocol decoders—all available without internet access.
- Offline-first capability - Fully functional in air-gapped or low-connectivity environments; all tools run client-side with no external API calls or cloud dependencies.
- Multi-deployment options - Deploy via Docker (
docker run -p 3000:3000 lissy93/networking-toolbox), static files (npm run build:static), GitHub Pages, Vercel, Netlify, or Node.js server.
- Mobile-optimized interface - Responsive UI designed for use on tablets and mobile devices in field operations or data centers with limited screen space.
- Light/dark mode and theming - Customizable visual appearance to reduce eye strain during long troubleshooting sessions, with persistent user preferences.
- Bookmarking and multi-language support - Save frequently used tools and switch between languages for international team collaboration.
Common Use Cases
- Building a secure air-gapped network audit station - Sysadmins in government or financial institutions use this tool on a dedicated laptop to validate IP ranges, subnet masks, and port configurations without exposing sensitive data to external services.
- Troubleshooting network outages in remote locations - Field technicians deploy the app via Docker on a Raspberry Pi to diagnose DNS resolution, ping latency, or CIDR mismatches without cellular data.
- Problem → Solution flow: No internet access during server migration → Use offline CIDR calculator to verify subnet compatibility - When migrating servers between data centers, engineers use the tool’s IP subnet calculator to confirm overlapping ranges without relying on online tools that may be blocked.
- DevOps teams managing multi-cloud infrastructure - Teams use the static build hosted internally to standardize network tool access across AWS, Azure, and on-prem environments, ensuring consistent diagnostics without varying third-party tool availability.
Under The Hood
The Lissy93 Networking Toolbox is a comprehensive Svelte-based web application designed to provide a suite of networking utilities through a modern, component-driven interface. It integrates both frontend and backend capabilities to offer a unified platform for IP addressing, CIDR manipulation, DNS management, and network diagnostics.
Architecture
A modular SvelteKit application with clear separation of concerns and well-defined component structures.
- Component-based architecture organized into distinct folders for tools, common UI elements, and global furniture
- Clear division between UI components and utility functions to support maintainability
- Use of SvelteKit’s built-in hooks for consistent error handling and request lifecycle management
Tech Stack
A modern web stack built with Svelte, TypeScript, and a robust ecosystem of development tools.
- Developed using Svelte 5 and TypeScript for enhanced type safety and reactive UI components
- Powered by Vite for fast development and optimized production builds
- Comprehensive testing ecosystem including Vitest, Playwright, and Jest-compatible utilities
- Leverages Node.js for backend API functionality and Docker support for containerized deployments
Code Quality
Well-structured codebase with consistent patterns, strong type safety, and extensive test coverage.
- Abundant test coverage across API endpoints and component logic with dedicated test suites
- Comprehensive error handling using global try/catch blocks and localized exception management
- Consistent naming conventions and component organization that improve code readability
- Strong emphasis on TypeScript for type safety and reduced runtime errors
What Makes It Unique
A distinctive aggregation of networking tools in a single, developer-friendly SvelteKit application.
- Aggregates diverse networking utilities into a unified and accessible web interface with intuitive tool cards
- Offers both frontend UI and robust API layer for seamless integration into external systems
- Provides extensive documentation and usage examples via Swagger/OpenAPI standards
- Includes internal diagnostic tools for security analysis and network troubleshooting