Simbelmynë generates synthetic galaxy survey data using a hierarchical probabilistic simulator. It is a parallel code and thus can generate a large number of realizations of synthetic galaxy survey data. The package can simulate the physics of dark matter structure formation via non-linear models, survey geometry, manage galaxy bias and selection effects, and contains modules containing cosmic web classifiers and phase-space field estimators. Intended for use within cosmological analyses of real survey data, Simbelmynë has been developed as a self-contained, end-to-end generative process, with a focus on speed and accuracy at the relevant scales.