The Python package abcvoting is a research tool to explore and analyse approval-based committee (ABC) elections (Faliszewski et al., 2017;Lackner & Skowron, 2023). First and foremost, it contains implementations of major ABC voting rules. These are voting rules that accept as input approval ballots, that is, the (binary) preferences of voters expressing which candidates they like or support. The output is a fixed-size subset of candidates, called a committee. Different ABC voting rules represent different approaches how such a committee should be formed. For example, there is a trade-off between selecting only widely supported candidates and choosing a committee that represent as many voters as possible (Lackner & Skowron, 2020). Much of the recent research has focussed on developing ABC voting rules that reflect the preferences of voters in a proportional fashion.Lackner et al. (2023). abcvoting: A Python package for approval-based multi-winner voting rules.