Courier is a monospaced slab serif typeface commissioned by IBM and designed by Howard "Bud" Kettler (1919–1999) in the mid-1950s.

IBM did not trademark the name Courier, so the typeface design concept and its name are now public domain.

[1][2][5] As a monospaced font, in the 1990s Courier found renewed use in the electronic world in situations where columns of characters must be consistently aligned, for instance, in computer programming.

Twelve-point Courier New was also the U.S. State Department's standard typeface until January 2004, when it was replaced with 14-point Times New Roman.

After giving it some thought, Kettler said, "A letter can be just an ordinary messenger, or it can be the courier, which radiates dignity, prestige, and stability.

"[1] With the rise of digital computing, variants of the Courier typeface were developed with features helpful in coding: larger punctuation marks, stronger distinctions between similar characters (such as the numeral 0 vs. the upper-case O and the numeral 1 vs. the lower-case L), sans-serif variants, and other features to provide increased legibility when viewed on screens.

Its thin appearance when printed on paper owes to its being "digitized directly from the golf ball of the IBM Selectric" without accounting for the visual weight normally added by the typewriter's ink ribbon.

[citation needed] ClearType rendering technology includes a hack to make the font appear more legible on screens, though printouts retain the thin look.

The styling of Arabic glyphs is similar to those found in Times New Roman but adjusted for monospace.

This Courier typeface, developed by Alan Dague-Greene with funding from John August and Quote-Unquote Apps, includes a true Italic style.

URW++[19] produced a version of Courier called Nimbus Mono L in 1984, and eventually released under the GPL and AFPL (as Type 1 font for Ghostscript) in 1996.

Thai Linux Working Group publish several typefaces as free and open-source software monospace.

[26][27] Many monospaced typefaces used as alternatives to Courier in coding are sans-serif fonts for on-screen legibility.

"Solid-style" ASCII art uses the darkness/lightness of each character to portray an object, which can be quantified in pixels (here in 12-point size): Courier, as a common monospaced font, is often used to signify source code.