The tools I've chosen from years of experience.

Ruby on Rails, Node.js, JavaScript, Ansible.

HTML5 CSS3 JavaScript Node.JS Ruby on Rails Symfony Ansible

Stable

Ruby on Rails is a mature framework for rapid application development.

Agile

Node.js is perfect for lightweight realtime projects or as part of microservice architechtures.

Universal

HTML5, CSS3, JavaScript are the common languages of the web and are universally available.

Safe

Experience of using DevOps tools like Ansible and AWS for creating secure, safe, robust cloud systems that give you peace of mind.