I use Flask for times when I need to create a REST API that interfaces with other Python code, or there is no specific reason why I'd want to use Node.JS. I prefer Flask because of its small learning curve, allowing me to get started coding as quickly as possible

I use ESLint to ensure my JavaScript code meets my team's coding standards, and to avoid known pitfalls. The extensibility allows me to write specialized modules that detect team-specific issues as they occur.

Paw allows me to interface with an API prior to starting UI work that requires the API. This helps me understand what data is required to be sent to the API, and what to expect back.

In cases where I develop the API, Paw helps me to test as I'm developing, ensuring changes I make aren't breaking other parts of the API.

Keen IO allows me to have a big data infrastructure without needing to set up and maintain the hardware and software. Their SDKs (available in many languages, my faves are Python and JavaScript) allow data to be stored, sliced and diced, and then visualized.

React is the first instance I've seen of a framework that provides truly reusable components, something I've been promised for many, many years.