Meteor.js is a full-stack JavaScript platform that simplifies web application development by allowing developers to use a single codebase for both the client and server sides. It provides an integrated set of technologies, including real-time data updates, a reactive templating engine, and a built-in package management system, streamlining the process of building modern and scalable web applications.
PostCSS is a popular open-source tool that enables web developers to transform CSS styles with JavaScript plugins. It allows for efficient processing of CSS styles, from applying vendor prefixes to improving browser compatibility, ultimately resulting in cleaner, faster, and more maintainable code.