Stephan Hoyer bio photo

Stephan Hoyer

Physicist, computational scientist and software engineer.


I am a core contributor and maintainer for many of the leading open source tools for scientific computing in Python; see my GitHub profile for details.


  • Xarray has become a standard tool for analyzing multi-dimensional datasets in Python (especially weather/climate data), and has contributed to hundreds of scientific papers. I created Xarray when I was a data scientist for The Climate Corporation, and now maintain it along with about a dozen other core developers. The project received hundreds of thousands of dollars in grant funding from the Chan-Zuckerberg Initiative and NASA, among others.
  • NumPy is the fundamental package for scientific computing with Python, with millions of users in academia and industry. I’m on the NumPy steering council and wrote a number of NEPs focused on inter-operability between NumPy and other array libraries.
  • JAX is a Google project focused on machine learning research. I have made and reviewed many contributions to JAX, with a focus on scientific use-cases such as jax.scipy.

Other projects I created:

  • Xarray-Beam is a library for distributed computing with Xarray and Apache Beam.
  • h5netcdf is an alternative implementation of the netCDF4 file-format in Python.
  • numbagg is an experimental project that uses numba and NumPy universal functions to write fast N-dimensional array aggregation functions with very little boilerplate code.
  • cyordereddict was a port of the Python standard library’s OrderedDict to Cython. It ran 2-6x faster.

In the past, I was a core developer for Dask and Pandas