Meet Markdown Web: a polished, open‑source Markdown editor that runs entirely in your browser, ships with a full AI toolkit (OpenAI + Anthropic), first‑class Git workflows, beautiful themes, export/print you can rely on, and a mobile‑ready UX. It’s the tool we wanted for everyday writing, docs, and technical notes—so we built it.
And with help from OpenAI’s Codex CLI, we moved from scaffolding to a production‑ready app in practically no time. Codex‑assisted generation let us stand up endpoints, components, and whole workflows quickly, while we focused on architecture, UX, and hardening.
Try it and star the repo: https://github.com/vultuk/markdown-web
Highlights at a glance
- In‑browser editor with live preview and split‑view
- AI built in: OpenAI + Anthropic, selection‑based edits, Q&A mode, model selection
- Precise cost tracking with per‑file usage logs and unified response formats
- Git integration: status, badges, add/stage, commit, push, clone, and context menus
- Always‑on Mermaid diagrams, syntax highlighting, and professional themes
- Export to PDF/Markdown with print‑perfect styling
- PWA install, mobile responsiveness, and accessibility
- Secure by default: password auth, session cookies, and safe key storage
- Settings that stick: layout, sidebar behavior, theme, AI provider/model, keys
AI that respects your workflow (and your wallet)
We’ve built a multi‑provider AI layer that feels native to the editor:
- OpenAI + Anthropic support with unified architecture and provider‑aware operations
- Dual‑mode AI: Adjust (modify content) or Ask (Q&A over your markdown)
- Selection‑based edits: target a paragraph, code block, or section—without touching the rest
- Model selection with smart aliasing/migration for seamless upgrades
- Accurate cost tracking across providers with:
- Per‑operation cost + token usage returned from every AI endpoint
- Per‑file log files with path‑based organization
- Status bar with cumulative cost visibility
- Consistent response parsing and robust sanitization
- Keys stored securely in local settings (with environment fallback)
Latest releases expanded pricing coverage, added path context to AI responses, and unified response formats so you get trustworthy numbers and cleaner analytics. Anthropic models (Claude Sonnet/Opus) and OpenAI models are both first‑class citizens.
Git, but friendly
You shouldn’t have to leave your editor to do the basics—or even most of the advanced stuff:
- Repository detection with smart Git badges on folders
- Real‑time file/repo status indicators (untracked, modified, deleted)
- Context menus (desktop right‑click, mobile double‑tap) for:
- Add/Stage, Commit (with modal), Push
- Clone repo into any directory
- Deleted file handling that “just works” (including
git rm --cached) - Detailed command feedback and strong error handling
From status to push, everything lives where you expect it: in the file explorer and context menus, with clean, VS Code‑inspired UI.
An editor you’ll actually enjoy
- Split‑view preview with draggable resizer and 50/50 double‑click reset
- Syntax highlighting with automatic light/dark themes
- Always‑on Mermaid diagrams with local‑first loading and CDN fallback
- Visual selection highlighting when AI modal is open
- Drag‑and‑drop file/folder moves with auto‑expand on hover
- Toast notifications and clear error reporting
- Mobile‑aware interactions and keyboard accessibility
Export and print you can trust
- One‑click PDF export and Markdown download
- Print output that mirrors your theme with professional typography
- Clean, multipage flow (no clipped boxes), smart page breaks, and link handling
Secure by default
- Password authentication (enabled by default) with session cookies
- Scrypt hashing, HMAC session signing, CSRF protections, and rate limiting
- API credentials sent with proper cookie handling across all endpoints
- AI keys stored locally in settings with masked input and validation
Settings that get out of your way
- Centralized settings modal for preview layout (full vs split), sidebar behavior (overlay vs inline), theme, AI provider/model, and API keys
- Preferences persist across sessions and devices
- Sensible defaults for desktop and mobile
Built at startup speed with OpenAI’s Codex CLI
Codex CLI accelerated our build dramatically:
- Rapid scaffolding of endpoints, components, and interfaces
- Iterative UX polishing with human‑in‑the‑loop refinement
- Faster hardening passes (error handling, validation, and logging)
- More time for product thinking, less time on boilerplate
The result: a high‑quality app shipped quickly—with a roadmap that keeps compounding.
Under the hood (for developers)
- TypeScript end‑to‑end, clean provider abstractions, and shared interfaces
- AI endpoints:
- /api/ai/status for capability detection
- /api/ai/apply for content modification (selection‑aware)
- /api/ai/ask for Q&A without altering content
- /api/ai/cost for per‑file summaries
- Git endpoints for add, commit, push, clone, and status
- Theming system with print/export integration
- PWA registration and offline‑friendly caching
- Robust path validation and safe file operations
- JSON_LIMIT env support (50 MB default) for large docs
What’s new
Recent releases focused on:
- Multi‑provider AI with Anthropic support and pricing/cost parity
- Accurate, unified cost tracking returned from every AI operation
- Model aliasing and smooth migrations across naming changes
- File‑path context in AI logs for cleaner analytics
- Full Git workflow (status, stage/add, commit, push, clone) with context menus
- Always‑on Mermaid with smarter loading for reliability
- Drag‑and‑drop file management and mobile‑first interactions
- Password auth by default, with better route ordering and cookie handling
- Professional SVG icon system, accessibility improvements, and responsive polish
The full changelog is available in the repo if you want to dive deep.
Call for contributors
We’re building in the open and would love your help:
- Star the project, file issues, and propose features
- Contribute themes, integrations, and UX improvements
- Share your workflows and ideas for the AI + Git experience
Start here: https://github.com/vultuk/markdown-web
If you write, document, code, or just love clean tools, we think you’ll feel right at home.