How can I build a web bug / URL token from scratch?

I’m really interested in Canary tokens and would like to learn more by building my own generator – And start with a simple URL token.

For example:
https://canarytokens.org/generate

It’s hard to find good materials on how to build canary (honeypot) tokens.
I know it’s quite nieche outside of infosec world, but not even my professor can point me to the right direction.

Ignoring the frontend – What else would I need to know? Is PHP enough? Do I need SQL databases?

Can someone point me to good sources? (tutorials, books, blogs…)