Though the Mozilla Foundation has been around for ten years now, they have only recently released their own font, Fira Sans, which is available as a free download from their site.

Fira Sans is available in four weights, including an italic variant for each weight, as well as a monospaced variant in two weights (regular and bold).

The typeface itself was designed by notable type aficionados Erik Spiekermann and Ralph du Carrois, and according to the style guidelines for the Firefox OS, “aims to cover the legibility needs for a large range of handsets varying in screen quality and rendering.”

It’s a practical take and a logical approach from the folks at Mozilla, with the availability of Firefox on so many mobile platforms now; to have a font that is clear and legible at most sizes and display qualities. Spiekermann also designed FF Meta, the original font used by the Firefox OS, and it’s clear that Fira Sans is heavily based on FF Meta. The decorative flair of FF Meta is toned down a great deal in Fira Sans, most likely for legibility’s sake, but the basic forms of each letter are highly similar.

True to its intent, text written out in Fira Sans is clear and easily readable at large and small heights. The style guidelines explain which weights and sizes of Fira ought to be used to fulfill various roles both web design as well as how the font can be used in a mobile interface (looking toward a Firefox OS phone or tablet in the future, perhaps?) or for mobile apps. It’s a crisp, clean font, and a smart move for the Mozilla brand as a whole.

What do you think of Fira Sans? Have you used it in a project? Let us know in the comments.