tbro/rakers

Rakers is a small command-line program written in Rust that takes a web page that depends on JavaScript and returns the page after the JavaScript has finished running. Many modern websites send back a near-empty HTML shell and then build the visible content with code from frameworks like React, Vue, Angular, Svelte, or Preact. Rakers simulates running that code so the result is plain HTML that a search crawler, scraper, or archival tool can read without needing a real browser. The project is sold on two numbers: starting up in milliseconds rather than 1 to 2 seconds, and using around 10 megabytes of memory rather than around 300. The README is clear that it gets these numbers by giving up some compatibility breadth. Page parsing is done by html5ever, the same HTML5 parser used inside the Servo browser project. JavaScript execution uses one of two engines, picked when the program is built: QuickJS, a small C engine wrapped in Rust, which is the default, or Boa, a pure-Rust engine that needs no C compiler but may stop working on large modern bundles. Using the tool is direct. You can pass it a URL, an HTML file, a JavaScript file, or you can pipe HTML on standard input. By default it prints the rendered HTML to standard output, but the -o flag writes to a file. Other flags let you set the user agent, add request headers, limit how many external scripts get fetched, set a per-script time limit, or filter the output to elements that match a CSS selector. Three output modes are useful for different jobs. The pretty flag indents the HTML for human reading. The json flag returns a small object with the raw size, the rendered size, and the HTML string, which is handy for scripts. The diff flag shows a side-by-side comparison of the page before and after running scripts. A clean mode strips out script tags and preload hints to produce a static snapshot like the kind that prerendering services give to search bots. Installation is either downloading a single prebuilt binary for Linux x86-64 or macOS Apple Silicon, or building from source with cargo install.