Emoji are pictographic symbols encoded in Unicode, used to visually express emotions and concepts in text communication. As of 2024, over 3,000 emoji are registered in Unicode.

Counting emoji characters is complex. Many emoji are located outside the BMP, requiring surrogate pairs in UTF-16 (2 code units). Additionally, skin tone modifiers and ZWJ (Zero Width Joiner) sequences mean a single emoji can consist of multiple code points. Emoji and Unicode guides explain these mechanics in detail.

In UTF-8, emoji consume 4 bytes each. Database VARCHAR columns need utf8mb4 encoding to store emoji.

Social media character limits typically count emoji as 1 character (or 2 on some platforms). Social media communication books discuss effective emoji usage.