Glossary
Key terms about emoji and Unicode, explained clearly.
Codepoint - the address of every character in Unicode
A codepoint is the unique hexadecimal number assigned to each character in Unicode. Learn how codepoints work, how to read them, and why emoji codepoints matter for developers.
Last updated: 2026-08-02Custom emoji - what they are and how teams use them effectively
Custom emoji let teams and communities upload their own image-based reactions, separate from Unicode. Learn how they work, where they live (Slack, Discord, Mastodon, GitHub), governance, and the failure modes of unmanaged collections.
Last updated: 2026-05-27Emoji fallback - what happens when an emoji can't be rendered
When a device can't render an emoji, what does it show instead? Learn the layered fallback chain (combined glyph, separate components, monochrome, tofu), why fallbacks differ across platforms, and how to design content that survives all of them.
Last updated: 2026-08-12Emoji shortcode - what :smile: actually means
Emoji shortcodes are :colon-wrapped: text shortcuts that render as emoji in supporting apps. Learn the history, the leading registries (CLDR, Slack, GitHub), conventions, and where shortcodes work and don't.
Last updated: 2026-05-27Emoji vendor - the design teams behind every smiley you see
Apple, Google, Samsung, Microsoft, Meta, JoyPixels, Twemoji. Each emoji vendor designs its own visual interpretation of Unicode codepoints. Learn who they are, how they differ, and which one to use when.
Last updated: 2026-05-27Emoji version - the release cycle that decides what your phone can show
Unicode and Emoji versions follow a yearly release cycle. Learn how versions are numbered, when new emoji become available across platforms, and why your device may not show last year's additions.
Last updated: 2026-07-05Grapheme cluster - what it is and why it matters for character counting
A grapheme cluster is what humans perceive as a single character, even when it's built from multiple Unicode codepoints. Learn the definition, why emoji and combined characters need it, and how to count them correctly.
Last updated: 2026-05-27Regional Indicator - the trick behind country flag emoji
Country flag emoji aren't single Unicode characters. They're pairs of Regional Indicator Symbols (Latin letter equivalents) that combine into flags using ISO 3166 country codes. Learn how the system works and where it falls short.
Last updated: 2026-05-27Skin tone modifier - what it is and how to use it correctly
Skin tone modifiers (U+1F3FB-U+1F3FF) let people customize the skin color of human emoji. Learn how the codepoints work, the Fitzpatrick basis, supported emoji, and etiquette guidelines.
Last updated: 2026-05-27Tag sequence - the mechanism behind sub-national flag emoji
Tag sequences are the Unicode mechanism that produces sub-national flags like England, Scotland, and Wales. Learn how they work, why they're so much more complex than regional indicator flags, and which platforms support them.
Last updated: 2026-05-27UTF-16 - the encoding behind JavaScript strings
UTF-16 represents Unicode codepoints in 2 or 4 bytes using surrogate pairs. Learn how it works, why JavaScript and Java use it internally, and the gotchas that surface when handling emoji.
Last updated: 2026-05-27ZWJ (Zero Width Joiner) - what it is and how it works
Zero Width Joiner (ZWJ) is an invisible Unicode character that combines multiple emoji into a single glyph. Learn how it works, where it's used, and why sequences sometimes break.
Last updated: 2026-05-26