Why I Built Openmark: A Markdown Editor for the AI Era
I built a native macOS markdown editor in one week with Claude Code. Here's why markdown needs to feel like a document, and how I shipped it.
Key Points
- Markdown is the perfect format for AI workflows, but no tool lets you view it like a real document.
- I built Openmark as a native SwiftUI macOS app in one week using Claude Code, solo.
- After ten years building software for clients, this is my first product with my name on it.
I’ve been running a software development agency since 2016. In that time, my team at Rotate has shipped hundreds of products for other people. But I’ve never shipped a product for myself. Today that changes. Openmark is live on the Mac App Store, and I want to tell you why I built it, how I built it, and what I learned along the way.
The Problem Nobody Talks About
Here’s something I kept running into as AI tools became part of my daily workflow: markdown is the lingua franca of AI. Every LLM speaks it natively. Claude outputs markdown. ChatGPT outputs markdown. When you’re working with AI coding tools, your project docs, your specs, your notes are all better off in markdown because AI tools can read and write them without friction.
But try reading a raw markdown file. It’s fine for short notes. For anything longer than a few paragraphs, it’s a mess of hashtags, asterisks, and backticks. You’re reading syntax, not content.
The alternative is Word docs. DOCX files look great, but they’re heavy. AI tools struggle with them. They carry formatting metadata that bloats the file and confuses models. Every time I tried to feed a Word doc into an AI workflow, something broke. The formatting garbled, the content got misread, or the tool just choked on the file size.
I wanted something in the middle. Markdown’s lightweight simplicity with a document’s readability. A place where I could write in markdown and see it rendered beautifully, like reading a finished document. Not a code editor with a preview pane bolted on. Not a knowledge management system with graph views and 400 plugins. Just a clean, native tool for writing and reading markdown like it was meant to be read.
That tool didn’t exist. So I built it.
Not Obsidian. Not VS Code. Just Markdown.
The markdown editor landscape has a weird gap in it. On one side, you have VS Code. It’s a phenomenal code editor, but it treats markdown like source code. You’re editing in a monospaced font with line numbers. It’s designed for developers, not writers. The preview pane helps, but you’re still context-switching between raw text and rendered output.
On the other side, you have Obsidian. It’s powerful. I’ve used it. But Obsidian is a knowledge management system that happens to use markdown. The plugin ecosystem is massive, the graph view is cool, and the linking system is deep. It’s also complex. I don’t need a second brain. I need a markdown editor.
Openmark sits in the space between them. It’s a native macOS app built with SwiftUI. It renders markdown beautifully so you can read your files like documents. It has a split view so you can edit on one side and preview on the other. Syntax highlighting makes the raw markdown easy to work with. Diagrams and equations just work. And it feels like a Mac app because it is one. No Electron, no web wrapper, no startup lag.
The whole point is focus. Open a markdown file, read it or edit it, close it. That’s it.
How I Built It in One Week
I used Claude Code for the entire build. Day one, I scaffolded the SwiftUI project and got the basic editor working. By day two, I had split view and live preview rendering. The rest of the week was features: syntax highlighting, diagram support, math equations, text statistics, file management.
Claude Code was consistently fast throughout the whole process. I’d describe what I wanted in plain English, it would generate the SwiftUI code, and I’d test and iterate. The feedback loop was tight. Instead of spending hours reading Apple documentation and debugging layout issues, I spent that time making product decisions. What should the toolbar look like? How should the preview handle code blocks? What’s the right font size for rendered headings?
This is what AI-assisted development actually looks like for a solo builder. It doesn’t write the product for you. It handles the implementation while you focus on the decisions that matter. I knew what I wanted because I’ve been using markdown daily for years. Claude Code knew how to build it because it understands SwiftUI deeply. The combination was fast enough to go from idea to App Store in seven days.
Seven days. For a native macOS app with a polished landing page, full feature set, and App Store approval. Two years ago, this would have been a three-month project minimum.
The First Product With My Name On It
I need to be honest about something. After ten years of building software for clients at Rotate, shipping my own product felt different in ways I didn’t expect.
When you build for clients, there’s a buffer. The product has their brand on it. Their users experience it. If something is slightly off, the feedback goes to them first. You’re one step removed from the judgment.
With Openmark, there’s no buffer. My name is on the App Store listing. The landing page is my design decisions. The pricing is my call. Every feature choice, every UX decision, every word of copy reflects my taste and judgment. That’s terrifying and liberating at the same time.
The liberating part won. Building something you want to exist, without a client brief or a committee to approve it, is the most fun I’ve had building software in years. I made decisions in minutes that would have taken weeks of back-and-forth in a client engagement. I shipped features because I wanted them, not because a stakeholder requested them.
If you’ve been building for other people and haven’t shipped something of your own yet, I can’t recommend it enough. The stakes feel higher because they’re personal, and that energy makes the work better.
What’s Next
Openmark is $9.99 on the Mac App Store as a one-time purchase. No subscription, no upsell, no free tier with artificial limits. You buy it, you own it.
I have a list of features I want to add, but I’m going to let real usage guide the roadmap. The core is solid: write markdown, read it beautifully, stay focused. Everything I add from here should make that core experience better without making the app more complex.
If you work with AI tools, write documentation, or just want a clean way to read and write markdown on your Mac, give it a look. I built this because I needed it. I think you might need it too.