[StevePerkins]

It's basically invisible automation for creating and renewing LetEncrypt certs on App Engine.

The traditional process for installing a custom domain SSL cert on App Engine was very clunky. Involved running OpenSSL commands, cut-n-pasting PEM data, etc. If you were using LetsEncrypt, then it was more or less impossible to automate... you had to go through a tedious manual process every 3 months (including updating your app, to respond to the LetsEncrypt verification endpoint!).

[iamgopal]

I think they do not use letsencrypt . They use thier own SSL, since they are now licencing authority.

Edit: I am wrong. They use letsencrypt.

[StevePerkins]

I am hosting this project on App Engine, and have been using their SSL management for a couple of months now:

https://resumefodder.com/

A click on the browser padlock icon says that it's a LetEncrypt cert. Unsurprising, since Google is such a major sponsor. Also unsurprising that Google chooses to focus on their own branding rather than call attention to it.

[iamgopal]

You are right, I do have many domains and didn't bother to check it.