Link: https://github.com/seagreen/acme-pcf-specification
It’s a specification for a tiny 1977 programming language called PCF, with the intention that people can write implementations in different languages and then compare them.
It’s inspired by https://github.com/gothinkster/realworld, but since I’m not that interested in HTTP APIs I wanted to have something similar for another domain.
I might do another one later for either a tiny MMORPG or chat app, that would be especially fun since it would lend itself well to benchmarking.