This package provides a coalescent simulator that allows the rapid simulation of biological sequences under neutral models of evolution, see Staab et al. (2015) <doi:10.1093/bioinformatics/btu861>. Different to other coalescent based simulations, it has an optional approximation parameter that allows for high accuracy while maintaining a linear run time cost for long sequences. It is optimized for simulating massive data sets as produced by Next- Generation Sequencing technologies for up to several thousand sequences.