bigJson: huge JSON file viewer for macOS, Windows, and Linux

Open 100MB, 500MB, even multi-GB JSON files without freezing your editor. bigJson is a free, open-source desktop JSON viewer built with Tauri, Rust (simd-json), and React. Use it for log dumps, API exports, and analytics datasets that crash VS Code, Sublime Text, and Notepad++. An open-source alternative to Dadroit.

Download · Website · How to open a large JSON file

Download

Latest release: github.com/hi-malay/bigJson/releases/latest

• macOS (Intel + Apple Silicon, universal): bigJson_0.1.3_universal.dmg
• Windows (x64): bigJson_0.1.3_x64-setup.exe or bigJson_0.1.3_x64_en-US.msi
• Linux AppImage (x64): bigJson_0.1.3_amd64.AppImage
• Linux .deb (Debian/Ubuntu): bigJson_0.1.3_amd64.deb
• Linux .rpm (Fedora/RHEL): bigJson-0.1.3-1.x86_64.rpm

All builds are unsigned. First-launch workarounds:

• macOS: right-click → Open, or run xattr -cr /Applications/bigJson.app
• Windows: SmartScreen blocks it → click "More info" → "Run anyway"
• Linux AppImage: chmod +x bigJson_*.AppImage && ./bigJson_*.AppImage

Why bigJson (vs VS Code, Sublime, Notepad++, Online JSON viewers)

VS Code and other text editors treat JSON as editable text UTF-16 string in RAM, tokenizer, syntax highlighter, undo buffer, plugins. That's why they freeze on 100MB+ files. Online JSON viewers can't handle anything past ~10MB and you'd never paste private data there anyway. bigJson is a read-only viewer that parses the file natively in Rust, builds a flat index of every node, and renders only the rows visible on screen. RAM usage stays close to the file size instead of 3-10×.

Features

• Open huge JSON files instantly 100MB in under a second, no UI freeze.
• Virtualized tree millions of nodes scroll smoothly because only ~50 visible rows render at a time.
• Lazy expansion children load on demand, even arrays with hundreds of thousands of entries.
• Text search across keys and values (case-insensitive).
• JSONPath search $.users[*].email, $.orders[?(@.total > 1000)], etc.
• Copy node value (pretty-printed subtree) or copy JSONPath for any node.
• Drag-and-drop files onto the window, or use the ⌘O shortcut.
• Native macOS, Windows, and Linux builds. No browser required.
• Open source under MIT. Built with Tauri 2, Rust, and React.

Screens

Empty state drag-drop or ⌘O to open	Text search across keys + values
Lazy virtualized tree	JSONPath mode

Run

npm install
npm run tauri dev          # dev, ~1 min first compile
npm run tauri build        # release .app / .dmg

Test fixtures

node scripts/gen-fixtures.mjs    # tiny / small / medium JSON in fixtures/

Stack

React + Vite + Tailwind 4  ←→  Tauri commands  ←→  Rust (simd-json + flat index)

src/ is the frontend. src-tauri/src/ is the Rust core (parser.rs, index.rs, search.rs, commands.rs). The Index is a flat Vec<Node> plus a child_ids arena node-id lookups are O(1), no per-node heap allocations beyond the previews.

Not yet

Files larger than RAM, raw text view, diff editor, code-signing/notarization. v2.

FAQ

How big a JSON file can bigJson open? On a machine with 16GB of RAM it comfortably opens JSON files up to ~3GB. v2 will add memory-mapped streaming for files larger than RAM.

Is bigJson free? Yes MIT licensed, no telemetry, no ads, no sign-in.

Does bigJson work offline? Yes. It's a native desktop app no network calls, no cloud parsing, no data leaves your machine.

Does bigJson edit JSON or just view it? View only. The goal is fast inspection of large files; an edit mode would require an undo stack and other machinery that defeats the speed advantage.

Is bigJson a Dadroit alternative? That's the inspiration. bigJson is open-source and free. Dadroit is closed-source with a free tier.

Why does macOS / Windows warn on first launch? The release binaries are unsigned (no Apple Developer Program / Authenticode signing fees yet). See the Download section for one-line workarounds per OS.