Unicode Codepoints, UTF-8 Encoding, and Grapheme Clusters Explained

Working with international text, symbols, and modern emoji requires understanding how Unicode characters are represented in memory and UTF-8 byte streams.

Inspect characters and codepoints with the Unicode Character Inspector.

Key Unicode Concepts

• Code Point: The numeric index assigned to a character, written as U+0041 (Latin capital letter A).
• UTF-8 Encoding: A variable-length encoding using 1 to 4 bytes per code point (backwards-compatible with ASCII).
• Surrogate Pairs: In UTF-16 (used by JavaScript strings internally), characters with code points above U+FFFF require two 16-bit units.
• Emoji Zero-Width Joiner (ZWJ): Sequences of distinct emojis joined with U+200D to render a single composite glyph (e.g. 👨‍💻 = Man + ZWJ + Laptop).

Inspect invisible characters and byte representations using the Unicode Character Inspector.