wtf is onebox?

Onebox is a Ruby library that converts plain URLs into rich, visual previews. You know how when you paste a link into a chat or forum and it automatically expands into an embedded video player, image, or article preview? That's exactly what this does. It was originally built for the Discourse forum platform but was extracted into a standalone library so any Ruby application could use it. At a high level, you hand it a URL and it returns an HTML snippet with the relevant preview content. For example, a YouTube link becomes an embedded video player, and an Amazon product link becomes a preview with the product image, name, and description. It supports many popular sites out of the box and can handle pages, images, and videos. For sites that follow common web standards for embedding content (like Open Graph or oEmbed), it can often generate previews automatically. For sites that don't, developers can write custom "engines" to handle the transformation. This would be useful for anyone building a web application where users share links and you want those links to look good automatically. Forum software, social platforms, chat applications, or blogging tools could all benefit. If you're running a community site where members post links to articles, videos, or products, this saves you from building that preview logic yourself. One important note: this standalone version is deprecated and no longer maintained. The code has moved into the main Discourse repository, so anyone looking to use or contribute to it today should go there instead. The README also includes a development server so you can test how different URLs will render before integrating it into a project.