Teamsplat generates fair teams for 2-team games of less than ~8 players, by brute-forcing all the possible alternatives. The backend uses Servant and either PostgreSQL (because Heroku needed it) or SQLite. The frontend is a bloated single-page application notably using Grommet and Flowtype. Made with love for the Australian Age of Empires II community.
Teamsplat uses aeson-flowtyped – another project of mine – to generate flowtype type declarations for the JSON API that the backend exposes.