It's an Api Rest with the an endpoint returns the fibonacci result like to indicate below:
http://localhost:3000/api/fibonacci/6
npm i
npm start
For this solution, I use Nodejs and express because it's so easy to construct web app faster and scalable and flexible with the express framework.
For the fibonacci calculation I implemented a simple recursive functionality calculate the previous values in the fibonacci serie based a positive and integer number.
Restructure the project with typescript and patterns to improve the quality, sturdiness and typing.