Speedlify is a web application for continuous performance monitoring of websites. It uses Eleventy as a static site generator to display historical Lighthouse scores, Core Web Vitals, and page weight metrics for specified URLs. The system runs automated tests via the performance-leaderboard package (which wraps Lighthouse/Puppeteer), stores results as JSON files, and generates trend visualizations using sparklines and charts. Key architectural elements include: data configuration in _data/sites/, test execution in run-tests.js, result storage in _data/results/, and Eleventy templates for presentation. The application is designed for Netlify deployment with caching to preserve test results between builds.