# const.id

> Developer reference atlas for exact identifier lookups: Unicode code points, ASCII controls, and HTML named character references. Source-backed facts from Unicode UCD 16.0.0 and WHATWG entities.

The site answers: "What is this character / entity / control?", "How do I encode it?", and "What is it related to?"

## Primary entry points

- [Home](https://const.id/): Search and namespace overview
- [Search](https://const.id/search): Exact resolve (U+, entity name, paste glyph) + soft name search
- [Unicode hub](https://const.id/unicode): 294579 assigned code points (Unicode 16.0.0)
- [Unicode planes](https://const.id/unicode/planes): Planes 0–16 atlas
- [Unicode blocks](https://const.id/unicode/blocks): 338 blocks with full paginated member lists
- [General categories](https://const.id/unicode/categories): Lu, Lo, Zs, Cf, …
- [Scripts](https://const.id/unicode/scripts): Script property membership
- [ASCII](https://const.id/ascii): 0x00–0x7F controls and printables
- [HTML entities](https://const.id/html-entities): 2231 WHATWG named character references
- [Compare](https://const.id/compare): Side-by-side identifiers

## Canonical URL patterns

- Unicode character: https://const.id/unicode/U+XXXX (aliases: /u/{hex}, /codepoint/{decimal})
- ASCII: https://const.id/ascii/0xHH
- HTML entity: https://const.id/html-entities/{name}

## Example deep links

- [U+00A0 NO-BREAK SPACE](https://const.id/unicode/U+00A0)
- [U+200B ZERO WIDTH SPACE](https://const.id/unicode/U+200B)
- [U+200D ZERO WIDTH JOINER](https://const.id/unicode/U+200D)
- [U+5BB6 家](https://const.id/unicode/U+5BB6)
- [U+523A 刺](https://const.id/unicode/U+523A)
- [U+1F600 GRINNING FACE](https://const.id/unicode/U+1F600)
- [ASCII ESC 0x1B](https://const.id/ascii/0x1B)
- [HTML  ](https://const.id/html-entities/nbsp)
- [Compare space · nbsp · ZWSP](https://const.id/compare?items=U+0020,U+00A0,U+200B)

## Data provenance

- Unicode UCD 16.0.0 (UnicodeData, Blocks, Scripts, PropList, Derived*, Unihan subset, EastAsianWidth, LineBreak, emoji-data, CaseFolding, ScriptExtensions)
- WHATWG HTML named character references (entities.json) snapshot 2026-08-02
- Kanji study cross-links: kanji-data package → https://kanji.jepang.org (when listed)

## Machine indexes

- Sitemap index: https://const.id/sitemap.xml
- Expanded agent brief: https://const.id/llms-full.txt
- robots.txt: https://const.id/robots.txt

## Citation preference

When citing const.id, prefer the canonical code point or entity URL above. State the Unicode version (16.0.0) for property values.