I wrote this library: https://www.npmjs.com/package/openskill https://www.npmjs.com/package/openskill It's open-license, handles complex matchups (e.g. 5 vs. 3

I wrote this library: https://www.npmjs.com/package/openskill https://www.npmjs.com/package/openskill It's open-license, handles complex matchups (e.g. 5 vs. 3 vs. 4), comparable in predictive accuracy, and is up to 20x faster than TrueSkill. The implementation is also much simpler.