SSL

Self signed

mkdir -p flask_server/certs/
openssl req -x509 -newkey rsa:4096 -nodes -out cert.pem -keyout key.pem -days 365
mv cert.pem flask_server/certs/
mv key.pem flask_server/certs/

Echo what ever domain name you entered to /etc/hosts.

Ex: optimeyes.co

echo "0.0.0.0 optimeyes.co" | sudo tee -a /etc/hosts

Certbot (real purchased certs)

certbot

sudo snap install --classic certbot
sudo ln -s /snap/bin/certbot /usr/bin/certbot
sudo certbot certonly --standalone

You will get instructions on where it is on your machine. Copy to flask_server/certs folder.

When it expires in ~90 days:

sudo certbot renew