SpeedTest by OpenSpeedTest is a free and open-source HTML5 network performance estimation tool that measures bandwidth and connection speed directly in the browser.
The tool solves the problem of network speed testing without requiring client-side software or plugins by using only vanilla JavaScript and built-in web APIs like XMLHttpRequest, HTML, CSS, and SVG. It runs on any web browser from IE10 onwards and requires only a static web server such as NGINX, Apache, IIS, or Express. The approach is lightweight—the script file size is under 8 kilobytes gzip—and performs well because it avoids third-party frameworks and libraries entirely.
Organizations concerned with security in restricted environments benefit most from this tool, since it contains only static files with no server-side code that could introduce vulnerabilities or require security updates. The tool suits any project needing a self-hosted speed test that works across devices and display sizes, from desktop browsers to mobile. The user interface is built in SVG, making it responsive to any resolution. Server requirements are minimal: the web server must support HTTP/1.1 or newer, accept GET, POST, HEAD, and OPTIONS requests, allow POST to static files, and handle a client body size of at least 35 megabytes with timeouts greater than 60 seconds.
The project maintains a stable codebase with minimal churn, suggesting a mature tool that has been refined over time since its inception. Development activity shows selective, focused updates rather than constant feature additions, indicating the maintainers prioritize reliability and performance over rapid iteration.
