PyERFA is the Python wrapper for the ERFA library (Essential Routines for Fundamental Astronomy), a C library containing key algorithms for astronomy, which is based on the SOFA library published by the International Astronomical Union (IAU). All C routines are wrapped as Numpy universal functions, so that they can be called with scalar or array inputs.

The project is a split of astropy._erfa module, developed in the context of Astropy project, into a standalone package. It contains the ERFA C source code as a git submodule. The wrapping is done with help of the Jinja2 template engine.