Let’s Encrypt is a great service that automates deployment and renewal of SSL certificates, at a bargain price. For most situations where you have a regular OS, the default Certbot Acme client works well. However for more embedded solutions, like Ubiquiti’s Unifi Cloudkey this is not an option as there is no full Linux OS. After researching a few of the alternative options, Acme Shell was the clear winner. It runs using the Bourne shell, and has Unifi support built in.