FusionMD

FusionMD

From first word to final layout.

A native Mac document studio that combines a beautiful Markdown editor, an AI writing assistant, a template engine, and a professional publishing pipeline — all in one app. The only Markdown editor that exports directly to Affinity and InDesign.

macOS 14 Sonoma or later  ·  30-day free trial  ·  One-time purchase
Coming Soon to the Mac App Store

Not yet available — join the waitlist for 10% off at launch.

01

Write

A beautiful Markdown editor with live preview, focus mode, and AI assistance. Every document is plain Markdown — readable by any tool, exportable anywhere.

02

Create

A template engine with {{variable}} placeholders, typed fields, and conditional sections. Fill a proposal, contract, or report in under a minute.

03

Publish

Export to IDML — the format Affinity and InDesign speak natively. Tag content with style names and hand a perfectly structured file to your layout tool.

📐

The only Markdown editor that exports to IDML.

IDML is the professional layout format — the file format that Affinity and Adobe InDesign open. No other Markdown editor on the market can produce it.

FusionMD takes an AI-generated or hand-written document with named paragraph styles and exports a properly structured IDML file. Your layout tool opens it with heading styles, body text, captions, and pull quotes already tagged — ready to design, not ready to re-type.

Works with Affinity and Adobe InDesign. The IDML spec is open and widely supported.
✍️

A writing environment that stays out of your way.

Full CommonMark and GitHub Flavored Markdown with live syntax highlighting. Bold is bold while you type. Headings are large. Code is monospaced. A floating format bar keeps every Markdown element one tap away.

Focus Mode

Dims every line but the one you're writing. The rest of the document fades to the background.

Typewriter Mode

Holds your cursor in the center of the screen as you type — no more eyes chasing the bottom.

Live Preview

Split view updates as you type. Drag the divider between full editor, full preview, or anywhere between.

19 App Themes

Light, dark, and everything between — named color palettes that change the whole writing environment, not just a mode toggle.

🎨

Your writing environment, your color.

Most writing apps give you a light/dark toggle — if you're lucky. FusionMD ships with 19 named color themes covering the full spectrum from crisp white to deep espresso, with a dozen variations in between. Pick the environment you want to write in, not the one the developer decided on.

Each theme sets the editor background, sidebar, toolbar, and accent color as a coordinated palette — not just a tint applied over a fixed grey UI. Switch to Hot Coffee and everything goes dark brown with latte cream accents. Switch to Sandstone and the whole app becomes warm editorial cream. The writing surface you stare at for hours deserves to look the way you want it to.

Light
System Sandstone Minimalist Crystal Ice Golden Hour Health Pina Colada Tuscan Honey
Dark
Slate Forest Graphite Rosewood Indigo Flamingo Evergreen Hot Coffee Pumpkin Spiced Honey Winter Storm
🧠

AI that understands your document — not just your text.

The AI in FusionMD is not a chatbot tacked on. It knows whether you are drafting a blog post, filling a contract template, laying out a report, or scripting a screenplay — and it adapts its behavior accordingly.

  • Apple Intelligence — on-device, completely private. Requires Apple Silicon + macOS 26 + Apple Intelligence enabled. No API key. No data leaves your Mac.
  • OpenRouter — cloud-based, user-supplied API key. Choose from Claude, GPT-4o, Gemini, and more. Email content sent to OpenRouter under their privacy policy.
  • Neither — FusionMD is fully functional without AI. Write and export without any AI configuration.
📋

Templates with real power.

Build a document template with {{variable}} placeholders — typed fields, required-field enforcement, and boolean conditions that show or hide entire sections based on what you fill in.

Create the template once. Fill it in seconds. Save any document as a reusable template. Share templates as .fusiontemplate files.

Useful for: proposals, contracts, reports, interview write-ups, brief templates, recurring newsletters, and any document type you produce more than once.
🎬

A dedicated Fountain screenplay mode.

FusionMD is the only Markdown editor with a proper Fountain screenplay mode: Courier 12pt rendering, scene navigator, two-row format bar with Action / Character / Dialogue / Transition shortcuts, and industry-standard PDF export.

Screenwriters get a professional tool. Power users get one less app.

📊

Eight analysis tools, built in.

No context switching. Every writing analysis tool lives in the right panel.

Proofreader Readability (Flesch-Kincaid) Style clarity Adjective & adverb density Passive voice Filler words Dialogue checker Grammar tools

Also: 21 languages supported, multi-language document detection, and on-device translation.

🌍

21 languages. Set once, everything adapts.

Setting the document language is a single action that changes five things at once: spell checking, smart quotes, typographic spacing, AI context, and dialogue correction all switch automatically. You don't configure each feature separately.

Smart Quotes

The correct quotation style for the document's language, applied automatically as you type.

English"Hello"
French / Spanish«Bonjour»
German„Hallo"
Chinese (Traditional)「你好」

French Typographic Spacing

When the document language is French (Canada or France), a French Spacing button inserts the correct narrow no-break space before ! ? ; : — the convention used in professional French publishing.

English Variant Scanning

For US, UK, and Australian English: detects out-of-convention spellings and vocabulary (38 spelling pairs, 23 vocabulary pairs) and offers to convert in either direction.

Disabled for English (Canada) — both US and UK spellings are correct in Canadian English and Fusion won't flag them.

AI Writes in Your Language

The document language is passed to the AI on every generation request. Ask for a paragraph and it writes in the document's language — using correct vocabulary, spelling conventions, and punctuation style — without you having to say "write in French" each time.

Built for Canada's two official languages.

English (Canada) accepts both US and UK spellings — because both are correct. Fusion won't flag "colour" or tell you "centre" is misspelled in a Canadian document.

Français (Canada) is a fully implemented locale: fr-CA dictionary, guillemets (« »), correct French typographic spacing, and AI that writes in Quebec French.

Fusion is the only Mac document editor that treats English Canada and French Canada as the first-class, distinct writing environments they are.

On-Device Translation macOS 15+

On macOS 15 Sequoia or later, translate an entire document into another language — or just a selected passage — entirely on your Mac. Paragraph structure is preserved. No API key, no cloud service, no data sent anywhere. Powered by Apple's Translation framework.

Two modes: Full document → new window (original untouched) or Selection → in-place replacement (translate one paragraph while leaving the rest unchanged). Language packs are downloaded once by macOS and then run offline.

English (US)English (Canada)English (UK) English (Australia)Français (Canada)Français (France) EspañolItalianoDeutschSvenska РусскийPortuguês (BR)Português (PT) 中文 (简体)中文 (繁體)日本語한국어 हिन्दीWelshIrishScottish Gaelic
🎨

Typography that matches the document — not just the font.

Word and Pages give you a font picker. FusionMD gives you document conventions.

A Text Theme is a complete typography system: font family, body size, line height, paragraph spacing, first-line indent, heading hierarchy, table style, and page margins — tuned together for a specific kind of writing. Switch from Novel to Contract and every typographic decision updates: not just the typeface, but the conventions that make that document look correct.

Word's style sets change the font. They don't know that a legal contract double-spaces at 12pt with stepped-indent headings, that an academic paper follows APA 7th edition heading rules, or that literary fiction uses first-line indents with no inter-paragraph gap. FusionMD builds those conventions in — one click, everything right.

To Do List

System font with indented heading levels that double as section categories — a visual outline without a sidebar.

Minimal

Clean monospaced font, block paragraphs, narrow margins. Plain writing without distraction.

Typewriter

Courier New with first-line indents and uppercase chapter headings — the classic draft manuscript look.

Novel

Palatino serif, generous 1.85× leading, first-line indents, no inter-paragraph gap — longform narrative and fiction.

Contract

Times New Roman, double-spaced, stepped heading indentation following legal document conventions.

Academic

Georgia serif, double-spaced, APA 7th edition heading hierarchy — university papers and research.

Technical

System font, bold heading scale, monospaced code and blockquotes — developer docs and READMEs.

Report

Compact system font with progressive heading indents for business reports, proposals, and executive summaries.

Newsletter

Georgia serif with editorial proportions — newsletters, blog posts, and magazine-style writing.

Every theme is fully customisable. Save your own typography system as a custom theme and it becomes available across all your documents.

Simple, honest pricing.

Free Trial

30 days
no credit card required
  • Full editor — no feature limits
  • Templates and variables
  • IDML export
  • AI assistant (Apple Intelligence or OpenRouter)
  • Fountain screenplay mode
  • All eight analysis tools

Comparable to iA Writer ($49.99) — with templates, IDML export, and Fountain mode that iA Writer doesn't have.

Frequently asked questions

What does FusionMD use AI for?

FusionMD uses AI for four things: generating or expanding content (draft a paragraph, write a section, continue where you left off); rewriting and polishing (adjust tone, improve clarity, make it shorter); analysis and proofreading (the eight built-in writing tools); and context-aware assistance — the AI knows whether you are writing Markdown, filling a template, or building a screenplay, and adapts its suggestions accordingly. AI is optional: every feature except AI generation works without any AI configuration.

Can the AI write in languages other than English?

Yes. When you set the document language — say, French (Canada) or German — that language is passed to the AI on every generation request. Ask for a paragraph and the AI writes in the document's language with correct spelling conventions, vocabulary, and punctuation style. You never need to say "write in French" each time. This works with both Apple Intelligence and OpenRouter-connected models.

What are Boilerplates and how do I use them?

A Boilerplate is a reusable chunk of content — a paragraph, a section, a disclaimer, a signature block — that you have written once and want to insert repeatedly. Unlike a Template (which is a whole-document starting point), a Boilerplate is a piece you drop into any document mid-writing. Store your standard contract clause, your author bio, your product description — then insert it in one click from the Boilerplate panel. Boilerplates are stored on your Mac and work offline.

How do I use AI to build content for Affinity or InDesign?

Use AI to generate multiple distinct content blocks — a headline, a product description, a pull quote, a caption — each as its own document or section with the appropriate paragraph style applied (Heading 1, Body, Pull Quote). When you export to IDML, FusionMD maps those style names into the IDML file. Open the IDML in Affinity or InDesign and the content arrives pre-tagged and ready to flow into your layout. You can generate, review, and refine the text entirely in FusionMD before the layout app ever opens.

Can I use FusionMD without AI?

Completely. The editor, templates, boilerplates, IDML export, Fountain screenplay mode, all eight analysis tools, and the full language system work without any AI. You don't need an Apple Intelligence device, and you don't need an OpenRouter API key. AI is an optional layer on top of a fully functional writing and publishing tool.

What is the difference between a Template and a Boilerplate?

A Template is a whole-document starting point — a blank form with {{variable}} placeholders, required fields, and conditional sections that you fill in to produce a complete document. A Boilerplate is a reusable passage you insert mid-document at any point. Think of Templates as forms and Boilerplates as a clipboard of pre-written content. You can use both in the same document: start from a template, then insert boilerplates to fill the variable sections.

What file format does FusionMD use?

FusionMD saves documents as .fusiondoc files. A .fusiondoc is a plain Markdown file with a small metadata header that stores the document title, language setting, and variable values if the document was created from a template. You can open any .fusiondoc in a plain text editor and read the Markdown. FusionMD also opens plain .md files directly. Templates are saved as .fusiontemplate files and work the same way.

Do I need Affinity or InDesign to use FusionMD?

No. FusionMD is a complete writing tool without either. IDML export is the publishing bridge for users who do page layout, but it is one feature of many. If you write blog posts, reports, screenplays, or template-driven documents and never open a layout tool, FusionMD is still the right tool.

How is FusionMD different from iA Writer or Ulysses?

iA Writer and Ulysses are excellent focused Markdown editors. FusionMD goes further in three ways. First, templates: {{variable}} placeholders, typed fields, required-field enforcement, and conditional sections — neither iA Writer nor Ulysses has anything close. Second, boilerplates: a managed library of reusable content blocks. Third, IDML export: the ability to hand a properly tagged document to Affinity or InDesign. FusionMD is priced identically to iA Writer and adds capabilities neither competitor ships.

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