Maybe make it look like a spam email? :-)

Write a web server with a countdown that sends you regularly a link via email to reset the countdown.

That’s the first thing I thought about when I saw this post. As a kid I loved the secrets in this game. I don’t know if it just seems so because I’m not a child anymore but modern games don’t seem to have this kind of mystery.

You could use React Native, so the language would be Javascript / Typescript.