Python Open Source Waveform ExtractoR: An open source, python package to monitor and post-process numerical relativity simulations Author(s) : Daniel Johnson <dsjohns2@illinois.edu> E. A. Huerta <elihu@illinois.edu> Roland Haas <rhaas@ncsa.illinois.edu> Maintainer(s): Daniel Johnson, E. A. Huerta, Roland Haas License : <PICK ONE> 1. Purpose Numerical simulations of Einstein's field equations provide unique insights into the physics of compact objects moving at relativistic speeds, and which are driven by strong gravitational interactions. Numerical relativity has played a key role to firmly establish gravitational wave astrophysics as a new field of research, and it is now paving the way to establish whether gravitational wave radiation emmitted from compact binary mergers is accompanied by electromagnetic and astro-particle counterparts. As numerical relativity continues to blend with routine gravitational wave data analyses to validate the discovery of gravitational wave transients, it is essential to develop open source tools to streamline these studies. Motivated by our own experience as users and developers of the open source, community software the Einstein Toolkit, we present an open source, python package to monitor the status and progress of numerical relativity simulations, and to post-process the data products of these simulations to compute the gravitational wave strain at future null infinity. This new software fills in a critical void in the arsenal of tools provided by the Einstein Toolkit Consortium to the numerical relativity community.