As a common symbol throughout typographic history, the heart shape has found its way into many character sets and encodings, including those of Unicode. Some characters depict the shape directly, others reference it in a more derived manner.

In the 1990s, NTT DoCoMo released a pager that was aimed at teenagers. The pager was the first of its kind to include the option to send a pictogram as part of the text.^[1][2] The pager only had a single pictogram on its options, which was a heart-shaped pictogram. This is thought to be Shigetaka Kurita's first exposure to the use of digital symbols in text form. The pager received rave reviews in Asia which led to other companies in the region to consider using pictograms in the list of text characters. NTT DoCoMo then released another pager aimed at businesspeople, but this time dropped the heart pictogram from the characters on the pager. Following its release, there was an outcry by users that the pictogram was no longer available, and many customers switched to other providers that had now included a heart pictogram in their markup. This led NTT DoCoMo to reverse their decision and include the heart pictogram.^[3]

As the emoji became more popular, other heart colours were launched by Unicode. Since then, each heart color has been given its own meaning.^[4]

In early 2022, Middle Eastern news publications suggested that sending a Red Heart emoji on WhatsApp in Saudi Arabia could amount to harassment and if convicted, the sender could serve a maximum sentence of two years in jail.^[5]

A common emoticon for the heart is <3. In Unicode several heart symbols are available in text format:

In Code page 437, the original character set of the IBM PC, the value of 3 (hexadecimal 03) represents the heart symbol. This value is shared with the non-printing ETX control character, which overrides the glyph in many contexts.

The single Unicode character heart related emojis can be found on the Miscellaneous Symbols and Pictographs, Supplemental Symbols and Pictographs, and Symbols and Pictographs Extended-A ranges.

• Playing cards in Unicode