If it's something you plan on spending months on hoping it will return $$$, make sure you validate. If it's a little side project that you will build to learn a new programming language, api or framework just go for it and build, as you will learn a lot which is super beneficial whether the end project is a success or not - and have fun.
Change your host files (sudo nano /etc/hosts) and add:
127.0.0.1 myapp.local
Should be accessible inside of your browser at myapp.local:9000
Also, ngrok as mentioned by Swizec is cool but it generates its own url and not myapp.local.
ngrok is cool for testing on multiple devices no matter where they are. setup ngrok and forward the link to my brother on Windows for IE and my other one running Linux for whatever otherside of the planet. Pretty dope.
I'm using a Telegram bot that notifies me from both Github and Gitlab when changes happen. :)
integram.org
And I obviously have the Telegram app installed on my Mac.
amrith