A perennial problem for JavaScript-heavy web applications is how to make the dynamic portion of those pages available to search engines. Historically, developers have resorted to a variety of tricks, including server-side rendering with React, external services or prerendering content. Now Google Chrome's new headless mode adds a new ‘trick’ to the toolbox — Rendertron, a headless Chrome rendering solution. Rendertron wraps an instance of headless Chrome in a Docker container, ready to deploy as a standalone HTTP server. Bots that don't render JavaScript can be routed to this server to do the rendering for them. Although developers can always deploy their own headless Chrome proxy and associated routing machinery, Rendertron simplifies the configuration and deployment process, and provides example middleware code for detecting and routing bots.
