Fira Mono
Google Fonts · Carrois Type Design · 2013

A humanist monospaced typeface designed for code, offering warmth and legibility that most mono fonts lack.
About
Commissioned by Mozilla for the Firefox OS project, Fira Mono brings the humanist sensibility of Fira Sans into a fixed-width format. Its open counters and clear letterforms make it particularly well suited to coding environments and terminal interfaces. Broad script support including Cyrillic and Greek extends its usefulness across international developer tooling.
Classification
Fira Mono is a monospaced companion to Fira Sans, retaining humanist proportions and open apertures that improve legibility in code editors. Its three-weight range offers flexibility without sacrificing the warmth characteristic of the Fira family.