Introduction

K2F is a document format for pixel-identical, semantically editable documents. You author meaning as JSON; one reference engine compiles it, and every viewer paints the same output.

Package model

A .K2F file is a ZIP. You edit two layers; k2f pack / compile writes the third:

Layer	Path	What it is
Content	`content/root.json`	Semantic tree: stable `id`, `role`, and `content`. No coordinates, colors, or font sizes.
Theme	`styles/theme.json`	Appearance keyed by role (and optional variant). Fonts live here and under `assets/fonts/`.
Lock	`document.K2F.lock`	Compiled geometry and paint operations. Viewers and exports paint this. Do not hand-edit.

manifest.json sets page size and margins; assets/ holds fonts and images. Change content or theme, then relock.

Quick install

pip install k2f

Python 3.9+. Optional: npm i @openk2f/k2f for the web viewer; cargo install k2f for a CLI without Python. For the full author loop (skill folder, init_package.py, pack_verify.py), see Getting started.

Get started

Getting started — agent skill or CLI, first .K2F
Format spec — normative contract (container, processing, integrity)

Authoring

Copy golden nodes from the catalog into content/root.json children (keep id: "root"; do not replace the file with a catalog fragment).
Look up allowed keys in Allowed keys, then the matching file under schema/.

Topic guides:

Text — paragraphs, headings, lists, inline marks
Images — embedded bitmaps and SVG
Tables — inline tables
Layout — stack and grid
Theme and fonts — roles, variants, embedded fonts

Reference

Catalog — packable ex_*.json examples
Allowed keys — node, theme, and manifest fields
Format spec

Export

Markdown or JSON → packed .K2F → PDF, PowerPoint, Word, or InDesign. The lock is the source; each file is a drawing of it.

Export — pipeline and format comparison
PDF — fillable AcroForm by default
PowerPoint
Word
InDesign

Guides

Markdown conversion — Markdown ↔ K2F
Web viewer — embed <k2f-viewer> (serve packages over HTTP, not file://)

Permanent publish links (/v/{appearance_hash}) are documented in the K2F Skill (references/publishing.md).

Agents and tools

K2F Skill — npx skills add suzheng/k2f --skill k2f; workflows for create, convert, export, and embed · k2f.dev/skills/k2f
Playground — compile and preview in the browser
Verify — check a .K2F file for integrity banners

Project

Status and roadmap
Desktop reader (in development) — native lock executor (same rules as the web viewer)
Contributing · Security · Compatibility

Contributor internals (engine design, crate map): architecture/. Not part of the authoring path.