From keystroke to page render, this post traces a URL's hidden journey: the browser parses protocol, domain, and path; resolves DNS to an IP; establishes a TCP handshake; sends an HTTP request; the server validates, queries DBs, assembles assets, and returns headers, status, and HTML; the browser parses HTML/CSS/JS to paint the UI. It closes with performance wins - gzip, caching, image optimization, CDNs, and query tuning - that cut load times ~30%.