mklyml editor

A visual editor for mklyml documents — source editing, live preview, and style inspector in one view.

Open the Live Editor →  ·  Documentation  ·  GitHub

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Three panes, all synchronized:

Source — CodeMirror 6 with mklyml syntax highlighting, colored block gutters, autocomplete for block names and properties, inline validation.

Preview — Live rendered HTML in an iframe. Updates as you type. Supports WYSIWYG mode — edit text in the preview and changes are reverse-converted back to mklyml source.

Style Inspector — Context-aware panel that changes based on your cursor. On a block: see its properties. On a style block: see CSS controls — color pickers, spacing inputs, alignment buttons, dropdowns, sliders. The inspector reads each block's styleHints to show only relevant controls.

Try it →

What You Can Build

Newsletters — Load the newsletter kit with 14 blocks, 19 themes, and 17 presets. Write a newsletter in the editor, preview it live, compile to email HTML with the email plugin.

Documentation — Load the docs kit with code examples, callouts, tabs, API references. The mklyml docs site is built this way.

Any structured content — Cards, heroes, CTAs, images, lists, quotes. The 16 core blocks cover general-purpose web content.

How the Inspector Works

Cursor on...	Inspector shows...
--- newsletter/featured	Block properties — source, author, link, image
--- style block	CSS controls for the targeted block type
--- meta	Document metadata — title, subject, preheader
--- theme: ...	Theme variables and color palette
--- preset: ...	Preset spacing and typography

Style controls are generated from a data-driven schema:

• Color pickers for color, background, border-color
• Spacing inputs for padding, margin, gap
• Alignment buttons for text-align, justify-content
• Dropdowns for display, cursor, overflow, font-family
• Sliders for opacity, border-radius

Every change patches the --- style block in your source — the cursor adjusts by the line delta so the editor doesn't jump.

Email Output

The editor includes output tabs for compiled HTML and email-ready markup. With the email plugin, CSS is inlined and the output is ready for any email service provider.

Embed in Your App

import { MklymlEditor } from '@mklyml/editor';
import { CORE_KIT } from '@mklyml/core';
import { NEWSLETTER_KIT } from '@mklyml/kits/newsletter';

function App() {
  return (
    <MklymlEditor
      initialSource={source}
      kits={{ core: CORE_KIT, newsletter: NEWSLETTER_KIT }}
      onChange={(source) => console.log(source)}
    />
  );
}

Architecture

Source (CodeMirror) <-> Store (Zustand) <-> Preview (iframe)
                            |
                     Style Inspector
                            |
                     StyleGraph (immutable)

Source changes trigger recompilation through the mklyml compiler. Inspector changes mutate the StyleGraph immutably and serialize it back into the --- style block. The preview iframe receives compiled HTML + CSS.

Docker

# From the workspace root:
docker build -f milkly-mklyml/mkly-editor/Dockerfile -t mklyml-editor .

# Run on port 8080:
docker run -p 8080:80 mklyml-editor

The container serves the static build with nginx (~25MB image).

Development

bun install
bun run dev    # Vite dev server at localhost:4321
bun run build  # production build -> dist/

Built with CodeMirror 6, React 18, Zustand, and Vite.

Related

• mklyml — Core language (parser, compiler, style system)
• mklyml-kits — Newsletter kit (14 blocks, 19 themes, 17 presets) + Docs kit (15 blocks)
• mklyml-plugins — Email plugin (CSS inlining) + Docs plugin (anchors, tabs)
• mklyml-docs — Documentation site

Full documentation →