Note: This gist may be outdated, thanks to all contributors in comments.
adb is the Android CLI tool with which you can interact with your android device, from your PC
You must enable developer mode (tap 7 times on the build version in parameters) and install adb on your PC.
Don't hesitate to read comments, there is useful tips, thanks guys for this !
Prerequisites : the letsencrypt CLI tool
This method allows your to generate and renew your Lets Encrypt certificates with 1 command. This is easily automatable to renew each 60 days, as advised.
You need nginx to answer on port 80 on all the domains you want a certificate for. Then you need to serve the challenge used by letsencrypt on /.well-known/acme-challenge.
Then we invoke the letsencrypt command, telling the tool to write the challenge files in the directory we used as a root in the nginx configuration.
I redirect all HTTP requests on HTTPS, so my nginx config looks like :
server {