The new version of X.com's web app was built by five engineers working with AI coding agents in under six months. It loads pages significantly faster than the old web app over slow connections, and it already serves logged-out users and the pages that search engines crawl. This post covers why X.com was rebuilt, how the new web app is being rolled out, and how the old and new apps compare today. It also looks at the performance work completed since logged-out traffic moved over.