A self-hosted URL shortener: Shlink - Keep control over all your shortened URLs, by serving them under your own domains, using this simple yet powerful tool. https://shlink.io/
I was very surprised to find this mature, full-featured URL shortener. It’s written in PHP and includes Geoblocking so your shortener isn’t abused.
A Docker quick-start guide: https://lnk.clifmo.com/ljk13
It was mostly uneventful, to be honest. I downloaded the two apps (static admin and the php app), tossed them into /opt/www, and set up nginx to serve PHP. The config in the main app had a section for my Postgres settings and the docs gave the instructions on putting the default server configuration into the static site.
The only challenge was actually rather silly: I don’t use PHP so it took me a bit to understand why apt install php installed Apache when I had already installed nginx. Once I found php-fpm it was smooth sailing from there.