A high-performance JSONL file viewer built with Next.js, optimized for log analysis.

• PWA Support — Install as a native app on any device
• Drag & Drop — Simply drag .jsonl files onto the page to open
• Multi-Tab — Open multiple files in tabs, switch between them freely
• Virtual Scrolling — Handle large files with thousands of lines efficiently via react-window
• Three View Modes
  • Pretty — JSON syntax highlighting with color-coded keys, strings, numbers, booleans, and nulls
  • Raw — Original unformatted JSON line
  • Tree — Interactive tree explorer with expand/collapse, path selection, and value panel
• Keyboard Navigation — Arrow Up/Down to navigate objects, Ctrl+A to select content
• Line Size Display — Toggleable per-line byte size indicator (persisted via localStorage)

# Install dependencies
pnpm install
# Run development server
pnpm dev
# Build for production
pnpm build
# Start production server
pnpm start

Open http://localhost:3000 to use the viewer.

1. Drag and drop a .jsonl file onto the drop zone (or click Browse Files)
2. Use the filter bar to search objects by text content
3. Click any object in the left list to view its details
4. Switch between Pretty, Raw, and Tree tabs
5. In Tree view, click nodes to expand/collapse and inspect values in the right panel
6. Use ↑/↓ arrow keys to navigate between objects
7. Use the sort button to toggle ascending/descending order

• Next.js 16 — React framework with App Router and Turbopack
• React 19 — UI library
• react-window 2 — Virtualized list for high-performance rendering
• next-pwa — Progressive Web App support
• TypeScript 6 — Type safety
• pnpm — Package manager

MIT