JsonTreeViewer

A high-performance JSON viewer and editor for Windows — built as a native plugin for Seer, the quick-look file preview tool.

Screenshots

JsonTreeViewer is a professional-grade JSON tree viewer and navigator built with C++ and Qt 6, powered by simdjson 4.6.3 for blazing-fast parsing. Designed specifically for Seer users who need to preview, navigate, and analyze large JSON files instantly — without opening a full IDE.

Perfect for developers, data engineers, and anyone working with JSON APIs, config files, or data exports on Windows.

Features

🚀 Performance & Core Experience

• Ultra-large file support with pagination: Handles massive JSON files efficiently using strategy-based loading, lazy parsing, and memory-mapped I/O (Windows-optimized). Virtual pagination for giant arrays ensures smooth navigation even with millions of entries.
• Async multi-threaded search engine: Search runs in background threads, keeping the UI responsive during intensive operations. Real-time navigation to search results while indexing continues.
• Interactive breadcrumb navigation: IDE-style breadcrumb bar in the status area for quick navigation through deeply nested JSON structures, with path display and node statistics.

🎨 Visual & UI Enhancements

• Premium visual styling: Indent guide lines, syntax highlighting for strings/numbers/booleans, and Material Design theme-aware icons for a professional look.
• Inline color preview: Hex and RGB color values display with visual color chips directly in the tree view.
• High-DPI & theme adaptation: Fully rewritten DPI scaling logic ensures crisp rendering on 4K displays and all scaling factors. Seamless light/dark theme support.
• Enhanced status bar metrics: Detailed file metrics display with rich tooltips showing full path previews and data statistics.

🛠️ Interaction & Productivity

• Deep copy & export: Right-click menu includes "Copy Dot Path", "Copy Key/Value Only", and "Export Selected Fragment" for efficient data extraction.
• Customizable shortcuts: Configure keyboard shortcuts for common operations (e.g., Tab to toggle modes) to match your workflow.
• Optimized search experience: Search results now display type icons with improved typography and font rendering for quick data type identification.

🔧 Stability & Error Handling

• Precise parse error reporting: Invalid JSON now shows exact error location with visual guidance, not just vague messages.
• Critical bug fixes: Resolved UI freeze/deadlock issues with empty objects {} and fixed escape character parsing anomalies.
• Memory optimization: Memory-mapped direct subtree extraction significantly reduces memory spikes when copying large data blocks.

This release transforms JsonTreeViewer from a simple viewer into a professional JSON processing tool, solving the pain points of large data performance and deep navigation.

Building and Running

Requirements: Qt 6.8, CMake 3.16+.

1. Clone the Repository

   git clone https://github.com/ccseer/JsonTreeViewer.git
   cd JsonTreeViewer

2. Build

   cmake -B build
   cmake --build build

   This produces two outputs:

   • jsontreeviewer.dll — the Seer plugin
   • test_jsontreeviewer.exe — standalone viewer for testing

3. Install the plugin

   Copy jsontreeviewer.dll to your Seer plugins directory.

Use with Seer

Seer is the ultimate quick-look file preview tool for Windows — press Space on any file to instantly preview it without opening a full application. JsonTreeViewer extends Seer with professional JSON viewing capabilities.

The perfect workflow:

1. Browse files in Windows Explorer
2. Press Space on any .json file
3. Instantly preview, navigate, and search JSON data in a beautiful tree view
4. No need to open VS Code, Notepad++, or any heavy editor

Why this matters:

• Instant preview: See JSON structure in milliseconds, not seconds
• Stay in flow: No context switching between Explorer and your editor
• Handle any size: From tiny config files to multi-GB API responses
• Professional tools: Breadcrumb navigation, syntax highlighting, color previews, and more

Get started:

1. Download Seer — the quick-look tool for Windows
2. Install JsonTreeViewer plugin (see instructions below)
3. Press Space on any JSON file to preview instantly

Visit 1218.io to download Seer and explore the full plugin ecosystem.