  Context: StePar is an automatic code written in Python 3.X designed to
compute the stellar atmospheric parameters Teff, log(g), [Fe/H], and of
FGK-type stars by means of the EW method. This code has already been
extensively tested in different spectroscopic studies of FGK-type stars with
several spectrographs and against myriads of Gaia-ESO Survey UVES U580 spectra
of late-type, low-mass stars as one of its thirteen pipelines.
  Aims: We describe the code and test it against a library of well
characterised Gaia benchmark stars. We also release the code to the community
and provide the link for download.
  Methods: We carried out the required EW determination of Fe I and Fe II
spectral lines using the automatic tool TAME. StePar implements a grid of MARCS
model atmospheres and the MOOG radiative transfer code to compute stellar
atmospheric parameters by means of a Downhill Simplex minimisation algorithm.
  Results: We show the results of the benchmark star test and also discuss the
limitations of the EW method, and hence the code. In addition, we found a small
internal scatter for the benchmark stars of 9 +- 32 K in Teff, 0.00 +- 0.07 dex
in log(g), and 0.00 +- 0.03 dex in [Fe/H]. Finally, we advise against using
StePar on double-lined spectroscopic binaries or spectra with R < 30,000, SNR <
20 or vsini >15 km/s as well as stars later than K4 or earlier than F6.
