I've searched for this three times this week, so I figured I'd better make sure I have a copy of it.
python -m SimpleHTTPServer 8000
Navigate to the project directory in the terminal and do that command. Then http://localhost:8000 will server up that directory (as in, it's `index.html` file).
python3 -m http.server --cgi 8080
php -S localhost:2222
npm i -g serve serve