What is Hotwire and Turbo in modern Rails?

Hotwire (HTML Over The Wire) is Rails 7's approach to building modern, reactive UIs without heavy JavaScript frameworks. Turbo Drive intercepts link clicks and form submissions, replacing page content via fetch without full page reloads. Turbo Frames allow partial page updates — only the framed section is replaced. Turbo Streams enable real-time updates over WebSockets or SSE, allowing the server to push DOM changes (append, replace, remove elements). Stimulus is a lightweight JS framework for adding behavior to HTML. Hotwire lets you build SPAs-like experiences with server-rendered HTML.