Emoji
Picture characters encoded in Unicode, born on Japanese phones in the late 1990s, drawn differently by every platform, and built from sequences of code points that break naive string handling.
Emoji are pictographs encoded as text characters, so they can be typed, sent, and searched like letters. The word is Japanese, from e (picture) and moji (character), and its resemblance to "emotion" is a coincidence.
Before them came emoticons, faces built from punctuation. The computer scientist Scott Fahlman proposed :-) and :-( on a Carnegie Mellon online message board in 1982, to mark jokes that readers kept taking seriously. Japan developed kaomoji that read upright rather than sideways, such as (^_^).
The first emoji set appeared in 1997 on a phone from J-Phone, a carrier later absorbed into SoftBank. The best known early set was drawn by Shigetaka Kurita for NTT Docomo's mobile internet service in 1999: 176 symbols on a 12-by-12 pixel grid, now in the collection of the Museum of Modern Art. Each Japanese carrier had its own incompatible set, until pressure from Google and Apple got 722 emoji added to Unicode in 2010. Oxford Dictionaries named the face with tears of joy its 2015 word of the year.
Under the hood, emoji are a stress test for character encoding and text handling:
- Outside the basic range. Most emoji need four bytes in UTF-8 and two code units in UTF-16, so a single emoji has a string length of 2 in JavaScript.
- Modifiers. Five skin tones, added in 2015, follow a base emoji as a separate code point.
- Sequences. A zero-width joiner fuses emoji into one: the four-person family is seven code points and eleven UTF-16 units. Flags are pairs of letter symbols for a country code.
- Presentation. Some symbols, like the heart, exist as both text and emoji, selected by an invisible variation selector.
One visible character can therefore be many code points, so code that cuts strings by length can split an emoji in half and leave garbage; see Text Truncation.
Every platform draws its own designs, so the same character can look different to sender and recipient. A 2016 study found people disagreed widely on the meaning and even the sentiment of common emoji, especially across platforms. Designs also change: Apple redrew the pistol as a water gun in 2016, and other vendors followed. Fonts carry them as color glyphs, in several competing formats.
Meaning is set by use rather than design. Emoji soften tone, mark irony, and stand in for gestures that text lacks. Their senses drift, as when the skull came to mean laughing.
In interfaces, emoji can add warmth to Microcopy, but a Screen Reader reads out each one's full name, so a line of them becomes a long recitation, and they are no substitute for clear Iconography. Their names and keywords are localized, so search and pickers need care across languages.
See also2
Input Method
The software layer that turns keystrokes into text for writing systems with far more characters than a keyboard has keys, such as Chinese, Japanese and Korean, by letting people type sounds or shapes and choose from candidates.
Systems & Tooling8 connections
SMS
Text messages of up to 160 characters sent between mobile phones, designed in the 1980s as a side feature of the GSM standard and grown into a global habit, a login code channel, and a fraud vector.
Networks & Distribution9 connections
Linked from6
- Character EncodingSystems & Tooling
The mapping between characters and bytes, and the source of a specific family of invisible bugs.
- Country CodeData & Content
The standard two- and three-letter codes for countries and territories maintained under ISO 3166, used in software, addresses, domain names, and flags, and a steady source of edge cases because borders, names, and recognition change.
- IconographyDesign & Interface
The design and use of small symbolic images in interfaces and signage, which are quick to recognize when familiar and surprisingly ambiguous when not.
- Input MethodSystems & Tooling
The software layer that turns keystrokes into text for writing systems with far more characters than a keyboard has keys, such as Chinese, Japanese and Korean, by letting people type sounds or shapes and choose from candidates.
- Internationalized Domain NameWeb Platform
Domain names written in non-Latin scripts and accented letters, made to work in an ASCII-only DNS by encoding them as xn-- strings, and the browser rules that decide when to show the real characters and when to show the code to block lookalike attacks.
- SMSNetworks & Distribution
Text messages of up to 160 characters sent between mobile phones, designed in the 1980s as a side feature of the GSM standard and grown into a global habit, a login code channel, and a fraud vector.