I really like endoflife! It's great for looking up dates with a consistent UI and also codenames - I could never learn that Debian Bullseye was 11 or all the other silly codenames so I look them up here. Thank you!

We also do something similar on Datatig, which is a tool I'm writing for the general situation of crowdsourcing data in Git repos. It makes it easier for people to submit data and then creates usable data and handy websites. The static website output has an API which is just static JSON files. https://pypi.org/project/DataTig/ or https://datatig.readthedocs.io/en/latest/