CBDF Specification: Overview

Version 1.0 (Phase II)

Document: 00-Overview • Date: 2026-03-25

1. What is CBDF?

CBDF (Compact Binary Document Format) is a binary replacement for HTML/CSS designed to radically reduce the size of marked-up documents. A CBDF-formatted message can be as little as 1% of the size of an equivalent modern HTML email.

CBDF achieves this by:

Using 1 byte for page layout (256 predefined templates vs. hundreds of bytes of CSS/HTML)
Limiting colors to 65,536 (2 bytes vs. 7 bytes for CSS #RRGGBB)
Using a fixed font table of 4,096+ fonts (2 bytes vs. font-family strings)
Encoding all formatting as compact binary style records referenced by 1-byte indices
Using ASCII control characters (0x00-0x1F) as inline commands instead of verbose HTML tags
Placing binary resources (images) in a separate skippable section

2. Use Cases

QMail: Quantum-safe email (.qmail files)
QWeb: Web pages (.qweb files)
RAIDA: Client-server data exchange
Text messaging: Ultra-compact meta-only messages (14 bytes for "Hello")

3. Document Structure

[Meta] FS [Styles] FS [Text] FS [Resources] FS [Logic]

Section	Description
Meta	Document envelope (subject, from, to, etc.). Never compressed.
Styles	Visual formatting lookup tables. Compressed with Text.
Text	Marked-up body content (UTF-8 + control codes). Compressed.
Resources	Binary blobs (images, fonts). Never compressed. Skippable.
Logic	Executable code (Phase III, not yet implemented).

4. Specification Documents

Document	Description
`00-Overview`	This document
`01-Document-Structure`	Section layout, meta keys, compression, EOF
`02-Meta-Section`	Meta section: KV format, key table, mailbox format
`03-Styles-Section`	Style sub-tables, record formats, bit layouts
`04-Text-Section`	Control codes in text, worked examples
`05-Resources-Section`	Binary resource format, abortable downloads
`06-Logic-Section`	(Phase III, placeholder)
`07-Control-Characters`	The 32 ASCII control character assignments
`08-Color-System`	R5G6B5 encoding, transparency codes
`09-Font-System`	Font IDs, effects, custom fonts

5. Phases

Phase	Description	Status
Phase I	Plain text only (`qmail_cbdf.c`)	Implemented
Phase II	Styled text, images, nav bars, tables, layers	Current phase
Phase III	Logic section (BEAM/Elixir), forms, interactive features	Planned