I'm vain, so I have one domain for my personal site, and another for shortlinks. The personal site generates a text file, which the build of the shortlinks site uses when it builds.
I had Netlify set up to trigger a build of the shortlinks site after the personal site builds, but most triggers were redundant (I don't have them for notes etc.).
I decided to replace the hook with a build plugin. https://github.com/qubyte/qubyte-codes/blob/main/plugins/update-shortlinks/index.js