📝
Split-Pane Editor
Write Markdown on the left, see the rendered HTML preview on the right with synchronized scrolling. The preview updates in real time as you type with no manual refresh needed.
✦ Write. Preview. Publish.
A lightweight desktop Markdown editor.
PurplePlatypus is a desktop Markdown editor with a live preview pane that renders your Markdown as you type and an AI writing assistant powered by LLM APIs.
PurplePlatypus
macOS • Windows • Linux
README.md Live Preview AI Assistant
# Project Documentation **PurplePlatypus** makes writing Markdown a joy. - *Split-pane editor* with live preview - AI writing assistant for drafting & editing - Export to HTML, PDF, DOCX, TextBundle, or RTF ## Getting Started Open any `*.md` file and start writing. The preview updates **in real time** as you type. [Learn more](https://glowingcat.com) | Format | Support | |--------|---------| | HTML | ✓ Full | | PDF | ✓ Full | | DOCX | ✓ Full | | RTF | ✓ Full |
Features
Everything you need for Markdown writing.
🤖
AI Writing Assistant
Built-in chat panel powered by LLM APIs to help draft, edit, and improve your Markdown content. Supports OpenAI, Anthropic, Google, DeepSeek, Alibaba, Cerebras, Groq, Meta, Mistral, Moonshot AI, Perplexity, xAI, and local Ollama models.
🔤
Live Spell & Grammar Check
Real-time spell and grammar checking powered by LanguageTool with support for 31 languages. Right-click misspelled words for suggestions or add them to your personal dictionary. Language packs download on demand.
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Localization
Full UI localization in English, Spanish, French, German, Italian, Japanese, and Simplified Chinese. Select your language in Preferences. RTL content support (Arabic, Hebrew) in preview and AI chat.
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Cross-Platform
Runs on macOS (ARM64), Windows (x64, ARM64), and Linux (x64, ARM64) with native look and feel on each platform.
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Export & Import
Export to HTML, PDF, Word Document (DOCX), TextBundle, TextPack, RTF, or Plain Text. Import from HTML, Plain Text, RTF, or Word Document files, converting content to Markdown.
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TextBundle & TextPack
Open and export .textbundle packages and .textpack compressed archives with images in the assets subfolder. TextBundle directories appear as selectable files in the Open dialog on all platforms.
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Find and Replace
Search with Match Case, Wrap Around, Search Backwards, and Find in Selection. Find All opens a results window with highlighted matches you can click to jump to.
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Table Editor
Insert or edit GFM-style Markdown tables via a visual dialog. Create complex tables without remembering pipe syntax.
✏️
Markdown Formatting
Bold, Italic, Underline, Strikethrough, Superscript, Subscript, Headings, Links, Images, Lists, Block Quotes, Code blocks, and Math via menus and keyboard shortcuts.
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Line Numbers
A line number gutter on the left side of the editor that stays in sync as you scroll and type.
🧮
MathJax Support
Inline and block math equations rendered with MathJax in the live preview. Write LaTeX math notation directly in your Markdown.
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Multi-Window
Open multiple editor windows simultaneously. Window size, divider positions, and panel visibility are remembered between sessions.
⌨️
Keyboard Shortcuts
Full set of shortcuts for file operations, editing, formatting, find/replace, and navigation. Familiar ⌘/Ctrl key combinations.
🖨️
Print Support
Page Setup and Print using the native system print dialog. Export to PDF via the system's PDF output.
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Customizable
Configurable font family and size for editor, preview, and AI chat panes. Customize LLM vendor, model, API key, and chat bubble colors.
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CommonMark Extensions
Full CommonMark support with GFM tables, strikethrough, task lists, autolink, footnotes, heading anchors, image attributes, ins (underline), and YAML front matter.
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Syntax Highlighting
Code blocks in the preview and AI chat are syntax-highlighted via highlight.js with automatic language detection and light/dark theme support.
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Mermaid Diagrams
Mermaid code blocks are rendered as diagrams in both the preview and AI chat panes. Create flowcharts, sequence diagrams, and more directly in Markdown.
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Lightbox Viewer
Right-click any image or Mermaid diagram in the preview or AI chat to open it in a full-screen lightbox with zoom in/out, fit-to-window, and drag-to-pan for detailed inspection.
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Generic LLM Vendor
YAML-configurable API endpoint for any LLM service — corporate APIs, custom proxies, and more — with OAuth/IAM token exchange and configurable request/response format.
Screenshots
A beautiful environment for Markdown writing.
AI Writing Assistant
Built-in AI chat panel for drafting, editing,
and improving your Markdown content.
Table Rendering
GFM-style tables rendered in the live preview
with clean, readable formatting.
Code & Equations
Syntax-highlighted code blocks and MathJax
equations rendered in the live preview.
Table Editor
Visual table editor for creating and editing
GFM-style Markdown tables.
Pricing
Simple app licensing.
Buy PurplePlatypus once and use it to write Markdown with a live preview, AI assistance, and export to multiple formats.
$25 software license
A lightweight desktop Markdown editor with live preview and AI writing assistant.
- Split-pane editor with real-time live preview
- AI writing assistant with multi-vendor LLM support
- Export to HTML, PDF, DOCX, TextBundle, TextPack, and RTF
- Import from HTML, Plain Text, RTF, and Word Document
- Full Markdown formatting via menus and shortcuts
- Syntax highlighting and Mermaid diagrams in preview
- Table editor, Find/Replace, and MathJax support
- TextBundle and TextPack open and export
- Multi-window with session persistence
- Customizable fonts, colors, and preferences
- Cross-platform (macOS, Windows, Linux)
FAQ
Common questions
What is PurplePlatypus?
PurplePlatypus is a lightweight desktop Markdown editor built with Java Swing, featuring a split-pane layout with live preview and an AI writing assistant powered by LLM APIs.
What file formats does it support?
PurplePlatypus can open .md, .markdown, .txt, .textbundle, and .textpack files. It exports to HTML, PDF, Word Document (DOCX), TextBundle, TextPack, RTF, and Plain Text. It can import from HTML, Plain Text, RTF, and Word Document files.
What AI providers are supported?
PurplePlatypus supports OpenAI, Anthropic, Google, DeepSeek, Alibaba, Cerebras, Groq, Meta, Mistral, Moonshot AI, Perplexity, xAI, and local Ollama models. A Generic vendor option lets you connect to any LLM API via YAML configuration. Configure your preferred provider and API key in Preferences.
Which platforms are supported?
PurplePlatypus runs on macOS (ARM64), Windows (x64, ARM64), and Linux (x64, ARM64) with native look and feel on each platform.
Does the preview support math equations?
Yes. The live preview renders inline and block math using MathJax via the JavaFX WebView. On Windows ARM64, the preview falls back to a Swing-based renderer with reduced functionality.
What Markdown extensions are supported?
CommonMark with extensions for GFM tables, strikethrough, task lists, autolink, footnotes, heading anchors, image attributes, ins (underline), and YAML front matter.
Can the AI modify my document directly?
Yes. When the AI suggests a complete document replacement, you're given Allow/Reject buttons to accept or decline the changes.
What are the system requirements?
PurplePlatypus requires Java 21 or later (JRE is included in platform installers). It works on macOS, Windows, and Linux.
Do I need a license for each computer?
No, you only need one license that is good for all platforms and all computers that you as an individual own. Send an email to Glowing Cat Software for information about commercial licenses.
Is PurplePlatypus open source?
Yes. PurplePlatypus source is available under the GNU General Public License v3.0.
Can I download and use PurplePlatypus without a license?
Yes, purchasing a license is optional, but it helps support open source software development.
Ready to write better Markdown?
Download PurplePlatypus to write, preview, and export
Markdown with AI-powered assistance.
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