NetCheck – Professional Network Quality Testing Tool

A comprehensive network diagnostic tool built with modern web technologies. Features include:

• Real-time network speed testing (download/upload) • Multi-target latency testing (Google DNS, CloudFlare, etc.) • NAT type detection using WebRTC • BGP information lookup • Geolocation and ISP detection • Multi-language support (English/Chinese) • Progressive Web App (PWA) capabilities • Modern responsive design with dark theme

Built with vanilla JavaScript, no frameworks required. Open source and privacy-focused - all tests run client-side. Perfect for network administrators, developers, and anyone who needs to quickly diagnose network issues.

The tool provides detailed technical information while maintaining a clean, user-friendly interface. All network testing APIs are carefully selected for accuracy and reliability.