The San Francisco typeface has three main variants: SF for macOS, iOS, and iPadOS; SF Compact for watchOS; and SF Mono for the Terminal, Console, and Xcode applications. Several other variants exist for internal use by Apple. San Francisco was first introduced in watchOS only. The next year at WWDC, Apple released the watchOS font as SF Compact and at the same time introduced SF UI for OS X El Capitan and iOS 9. In macOS High Sierra and iOS 11, SF UI was succeeded by SF Pro. Note: SF has the codename SFNS in macOS and SFUI in iOS, regardless the official name. The main difference is that the sides of letters with round shapes, such as o, e, and s, are round in SF, whereas they are flat in SF Compact. The flat sides allow the letters to be laid out with more space between them, thereby making the text more legible at small sizes, which is particularly important for the Apple Watch. Both SF and SF Compact each have two optical sizes: "display" for large and "text" for small text. Compared to display, the letters in text have larger apertures and more generous letter-spacing. The operating system automatically chooses the display optical size for sizes of at least 20 points, and the text optical size otherwise. Additionally, included in macOS Sierra and iOS 10 is a new variant named SF Compact Rounded. It is used in the new contact placeholder icons introduced in the OSes. In iOS 12.2 beta, SF Pro Rounded was found. It was officially released on the Apple Developer website on June 3, 2019. SF Mono, which is a monospaced variant, was introduced at WWDC 2016. It is installed as default in Console, Terminal and Xcode. It was officially released on the Apple Developer website in August 2019. The SF Serif variant was showcased during the keynote at WWDC 2018 on June 4, 2018 when the all-new Apple Books app was introduced. This variant was exclusive to Apple Books in iOS 12, as a result, it was not available for download. It was later released in four optical sizes with six weights each, under the name New York on June 3, 2019, on the Apple Developer site. The font includes OpenType features for lining and old-style figures in both proportional and tabular widths. Despite Apple having a font with the same name with the bitmap format for the original Macintosh, it is unrelated to this design. The SF Hello variant was first introduced in 2016. It is restricted to Apple employees and permitted contractors and vendors, and is therefore not available for public use. This variant appears to be an intermediate optical size between SF UI Text and SF UI Display; however, some characters are tweaked, and the letter-spacing is adjusted specially for printing rather than displaying on screen. SF Cash can be found in the Apple Pay Cash app for iMessage. It includes a chiseled-style SVG color font titled "SF Cash Chiseled", a plain version titled "SF Cash Plain", and "SF Cash Text Condensed Semibold" which appears more condensed than "SF Pro Text Condensed Semibold". SF Shieldsfirst appeared in iOS 12.1, and is hidden in the GeoServices cache folder. It is also found in macOS Mojave's GeoServices cache. SF Camera was introduced on September 10, 2019 at Apple's keynote with the iPhone 11. SF Camera is the UI font for the Camera app on the iPhone 11 and the iPhone 11 Pro models. Phil Schiller mentioned it while explaining how much the camera updates are meaningful to Apple, and implied that it's that important to them that they created a new version of the font for it.
Usage
Since its introduction, San Francisco has gradually replaced most of Apple's other typefaces on their software and hardware products and for overall branding and has replaced Lucida Grande and Helvetica Neue as the system typeface of macOS and iOS since OS XEl Capitan and iOS 9. Apple uses it on its website and for its product wordmarks, where it replaced Myriad Pro. It is also used on the keyboard of the 2015 MacBook and on the 2016 MacBook Pro, replacing VAG Rounded. It is also used as Apple's corporate typeface. Apple restricts the usage of the typeface by others. It is licensed to registered third-party developers only for the design and development of applications for Apple's platforms.
