As a reminder, Let’s Encrypt has been providing sites with the X.509 digital certificates required to enable HTTPS (SSL/TLS) and encrypted communication for free since September 2015, when the first certificate for the helloworld.letsencrypt.org domain was issued.
Since August 2018, Let’s Encrypt has been trusted by all major browsers and operating systems, as well as by all major root certificate authorities (including those from Microsoft, Google, Apple, [...]