markjason
Lightning-fast native editor for Markdown, JSON, and .env files built for AI coding workflows
Free Utilities
Overview
markjason is a native macOS text editor laser-focused on three file types: Markdown, JSON, and .env. Built with SwiftUI, it launches in 0.3 seconds and uses around 100MB of RAM, making it ideal for the rapid file-switching demands of agentic coding workflows. Features include live file sync detection, a Markdown preview toggle, JSON validation with a collapsible tree view, .env value copying, token counting for AI prompts, and keyboard-first navigation. It deliberately avoids feature bloat with no Git integration, cloud sync, plugins, or accounts.
Minimum macOS: 14.0 (Sonoma)
Architecture: Apple Silicon, Intel
Key Features
- 0.3-second startup with ~100MB RAM usage
- Live file sync detection when other apps modify files
- Markdown editing with instant preview toggle via Command+E
- JSON validation with collapsible tree view and color-coded types
- .env file support with instant value copying
- Token counting for AI prompts
- Export files as shareable images
- Keyboard-first navigation with Command+K quick open
- Auto-detection of clipboard content format
