Apis and Microservices Projects - URL Shortener Microservice

The layout is not clear. It look ridiculous to change string to number. Even is not sayed the number should be unique. and to be saved. Why use a mongo if there is .env? and why body parser if is about url?
Why the videos now missing in all jobs? and in which lesson was a passing parameters from html input?
I am getting the when clicking at submit button, but the “-” make problem, to catch after new