# same font throughout bibliography

Consider this example:

\documentclass{report}
\usepackage[backend=bibtex]{biblatex}
\urlstyle{same}
\begin{document}
See \cite{aauu:2012kp}
\printbibliography
\end{document}


where testbibfont.bib is

@article{aauu:2012kp,
author         = "aauutt",
title          = "{The algorithm}",
journal        = "Journal",
volume         = "7",
year           = "2012",
pages          = "T10003",
doi            = "10.1089/1749-0221/7/11/T10003",
eprint         = "1204.2201",
archivePrefix  = "arXiv",
primaryClass   = "data-an",
reportNumber   = "BBB-12"
}


I already align the font of DOI with the rest of the text with \urlstyle{same} (different font while using url). That would be sufficient were it not for primaryClass which uses a different font:

How to have the font of main text everywhere in bibliography?

Indeed the arXiv eprint field format is pretty much the only place where biblatex has an explicit \texttt instead of \nolinkurl/\url which are governed by \urlstyle.

You have to modify the format a bit to remove the \tetxttt

\makeatletter
\DeclareFieldFormat{eprint:arxiv}{%
\ifhyperref
{\href{https://arxiv.org/\abx@arxivpath/#1}{%

The original definition can be found in biblatex.def, ll. 471-482.