Does the OFL require that you make the font source files available?

Hi! I’ve just read the open font license, and I cannot seem to find anything that requires the copyright holder to make the font source files available to the licensee. But for the OFL to be considered a free/libre license it would have to require access to source files. Can anyone clear up my confusion? Thanks!

Hi Fredrik -

This is a forum for SIL fonts, not the OFL in general, but briefly: Unlike other software, there is no clear definition of what could be used as font ‘sources’. For fonts there are many different possible types fo files and formats that can be opened in a font design tool and used to make other fonts: .vfb, .ufo, .glyphs, .sfd, .pfa, .pfb, .fea, .otf, .ttf. Even the last two in that list can be considered valid source formats, as they can be opened by common tools and modified to create derivatives.

For this reason the OFL does not explicitly require distribution of a font’s ‘source’ as the font itself is a valid source format. This is acknowledged to be sufficient to meet the Free Software Definition, Open Source Definition, and Debian Free Software Guidelines. This has been affirmed by both the FSF and OSI.

Hope that helps,


Just to expand a bit on what Victor has said: although it’s not a legal requirement of the license for the specific reasons that sources and the preferred form for modification are not 100 % clear and vary from tool to tool and from platform to platform, there is still a strong cultural trend to encourage the publication of full source files and a corresponding public build path (ideally converging towards UFO + fonttools). This is what we are doing for our projects (hosted on GitHub) and encouraging others to consider doing as well. It’s a case of encouraging people to think about the benefits rather than strictly mandating. I think our approach has worked very well. Mandating it at the time when the first OFL-ed project started to get published (back in 2007 or so) would have been a seriously limiting factor. Thankfully the font toolchain is making a lot of progress these days.

Are you aware that there are other OSI and FSF-approved licenses which don’t explicitly mandate source availability? They are still recognized as valid. So it’s your criteria for classification that probably needs adjusting.

Did you get a chance to look at the OFL-FAQ?

Hope that helps.

@VictorG @n7s Thank you both for your thourough explainations! It makes more sense now. I must apologize for my ignorance, I’m not too knowledgeable about licensing so I hope you’ll forgive me.

No problem! Happy to help.

No problem at all, we’re here to help. Wishing you success and a lot of fun with your font projects.