Hack is characterized by a large x-height, wide aperture, and low contrast design in order to be “highly legible” at common coding text sizes. Its “sweet spot runs in the 8px-12px range on modern desktop and laptop monitors,” Simpkins, creator of HACK, writes on GitHub. “Combine it with an HD monitor and you can comfortably work at 6 or 7px sizes.” As seen in the image above, there’s a heavier semi-bold weight in the regular font, and strategic serifs eliminate large gaps on each side of narrow characters. As Simpkins notes on the SourceFoundry site, this helps to distinguish glyphs like the lowercase l and number 1 at small text sizes.
Hack’s roots are in the libre, open source typeface community, and the project expands upon the contributions of the Bitstream Vera & DejaVu projects. (See a full contributors list here.) Simpkins has been working on the project throughout 2015, and he tweeted that this latest version includes “new open type features, changes in weights, significant changes in spacing, Powerline glyphs, and more.” The typeface now comes with four font styles: Regular, Bold, Oblique, and Bold Oblique.