In short green coding mean for us less IT resources in everything. This means
For two first bullets we use Bootstrap Studio for creating static web pages based on PWA. Bootstrap Studio web sites are also automatically responsive and fit on all screen sizes. All sites requires today at least some code in javascript. This code we create with node.js and produce from that code a javascript library for web application using webpack.
For last bullet we use on AWS Lambda functions. In non aws environment we use simple java based REST API methods that are calling database procedures and functions for executing the business logic and producing the response JSONs for clients. In short our API's role is mainly to be a gateway between client and database procedure and/or function.