Brennan's Gemini Blog
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I created a .md to .gmi converter for anyone to use.
Hi there, I made a client-side web application that converts Markdown files to Gemtext format, built with vanilla HTML, CSS, and JavaScript. Supports drag-and-drop upload, live preview, batch processing, and download.
Live demo: https://gemtext.brennan.day
External Dependencies
This project uses minimal external resources for functionality:
- marked.js v9 (CDN) — Markdown parser and lexer
- Loaded from https://cdn.jsdelivr.net/npm/marked@9/marked.min.js
- Used to parse Markdown tokens for conversion to Gemtext
- License: MIT
- JSZip v3 (CDN) — ZIP file creation library
- Loaded from https://cdn.jsdelivr.net/npm/jszip@3/dist/jszip.min.js
- Used for batch download functionality
- License: MIT or GPLv3
- Font Awesome 7.2.0 (CDN) — Icon library for UI elements
- Loaded from https://cdn.jsdelivr.net/npm/@fortawesome/fontawesome-free@7.2.0/css/all.min.css
- Used for all interface icons (upload, settings, download, etc.)
- License: CC BY 4.0 (Font Awesome) / CC BY-SA 4.0 (Font Awesome Free)
Overview
Gemtext is the native text format for the Gemini protocol, a simpler alternative to the web. This converter transforms standard Markdown into clean Gemtext while preserving essential structure and links.
- No server processing, everything runs in your browser
- Your files never leave your device
- Works offline once loaded
- Open source and privacy-focused
Features
- Drag-and-drop upload of .md, .markdown, and .txt files
- Live preview with rendered and raw Gemtext views
- Batch processing with ZIP download
- Settings modal for conversion options
- Responsive design for mobile and desktop
- Accessibility with ARIA labels and keyboard navigation
Usage
- Open https://gemtext.brennan.day in your browser
- Drag Markdown files onto the drop zone or click to select files
- View the converted Gemtext in the preview pane
- Toggle between rendered and raw views
- Download individual .gmi files or a ZIP archive of all files
- Adjust settings in the gear menu for different conversion behaviors
Conversion Rules
- Headings H4–H6 are downgraded to H3 (###)
- Inline links are extracted to => URL text lines
- Ordered lists become unordered (*)
- Nested lists are flattened with indentation
- Tables become preformatted blocks
- Images become => URL alt-text links
- Bold, italic, strikethrough, and inline code are stripped
- HTML tags are removed; entities are decoded
- Code blocks are preserved with language tags
Settings
- Link placement: After paragraphs or at document end
- Heading downgrade: Limit headings to level 3
- Table conversion: Preformat or skip
- List flattening: Flatten nested lists with indentation
- Image handling: Convert to links or skip
- Frontmatter: Strip or render as preformatted
- Line endings: LF or CRLF
- Source comments: Add conversion metadata
Development
Local Development
Then visit http://localhost:8765
Project Structure
Testing
The test/ directory contains edge-case Markdown files and their expected Gemtext outputs. Use these to verify conversion correctness:
Deployment
The app is designed for static hosting. Netlify configuration is included:
- netlify.toml — SPA routing and build settings
- No build step required — just deploy the files as-is
Privacy and Security
- All processing happens client-side in your browser
- No files are transmitted to any server
- No analytics or tracking
- No cookies or local storage beyond settings persistence
- Works offline after initial page load
Browser Support
- Modern browsers with ES6+ support
- Tested in Chrome, Firefox, Safari, Edge
- Mobile browsers supported
About
A 🍓 Berry House project by Brennan Kenneth Brown.
License
AGPL 3.0
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© 2026 Brennan - Content available under CC BY-SA