Unicode 6.0 first standardized emoji for worldwide digital text exchange.
Published in October 2010, Unicode 6.0 added 722 emoji characters, including many symbols that had previously existed mainly in Japanese mobile-phone systems. Standardization allowed different companies to encode the same underlying characters, even though their artwork could vary.
Emoji are not pictures embedded directly in a message. They are encoded characters, and a device uses a font or graphics set to display each character. This is why the same emoji can look different on Apple, Google, Microsoft, or Samsung devices.
A common mix-up is confusing Unicode standardization with the invention of emoji. Emoji originated in Japan during the 1990s, while Unicode later provided a global encoding framework. Subsequent Unicode releases added many more symbols, skin-tone modifiers, gender options, and regional flags.