Express.js is a simple Node.js framework for single, multi-page, and hybrid web applications.
A fullstack boilerplate provides a starter application that includes both frontend and backend. It should include database, auth, payments, user roles and other backend services to build a fully featured saas or webapps.
ESLint is a linter for JavaScript that analyzes code to detect and report on potential problems and errors, as well as enforce consistent code style and best practices, helping developers to write cleaner, more maintainable code.