Prune, shape, and navigate giant JSON trees — a browser extension JSON viewer built to stay smooth on 100k+ node payloads.

Install: Chrome Web Store · Firefox Add-ons

Screenshots

Features

Views

• Five view modes: Tree, Table, Formatted, Raw, and Schema (inferred JSON Schema, draft-07)
• Virtualized tree rendering — smooth scrolling and interaction on 100k+ node payloads
• Table view for arrays of objects — sortable columns, virtualized rows, works on query results too
• Collapsible/expandable tree view with level controls — press 1–8 to set depth, 0 to expand all
• Syntax highlighting for keys, strings, numbers, booleans, and null; URLs become clickable links
• Indent guide lines with hover highlighting

Query, search, and copy

• JMESPath query bar (Q) — filter and reshape the JSON; the result renders as a fully interactive tree
• Query relative to any node — "Query from here" seeds a node's path; append | expr to query inside that subtree, with autocomplete resolving keys against the scoped node
• Content search in a web worker with match navigation (⌘F / ⌘G, Enter / Shift+Enter); in table view, search filters the rows instead
• Hover any property to see its full JSON path — click to pin, then copy
• Per-node actions: copy any subtree's value, expand/collapse all children, "query from here" (ƒ query), or "query across all array items" (ƒ all, on nodes inside an array)
• Copy JSON to clipboard (C) — copies what the active view shows (raw, pretty, schema, or query result)
• Optional console access — opt in (Settings ⚙, off by default) to expose the payload as window.data

Fidelity

• Lossless big numbers — 64-bit IDs and high-precision decimals display and copy exactly as sent, where JSON.parse would silently corrupt them

Personalization and platform

• base16 theming — 13 bundled schemes plus your own custom themes, with auto/dark/light mode switching
• Per-site memory — the view mode, tree depth, and query/search history you use are remembered per origin and restored on your next visit; query/search history can be disabled in Settings
• Cross-platform builds (Windows/macOS/Linux) and a single package that works in both Chrome and Firefox

Installation

Install directly from the Chrome Web Store or Firefox Add-ons.

Prebuilt .zip packages are attached to each GitHub Release. To run from source, build it first — the dist/ folder is not committed:

npm install
npm run build

Chrome

1. Open Chrome and navigate to chrome://extensions
2. Enable Developer mode (toggle in the top right)
3. Click Load unpacked
4. Select the dist folder inside this project

Firefox

1. Open Firefox and navigate to about:debugging#/runtime/this-firefox
2. Click Load Temporary Add-on...
3. Select the manifest.json file inside dist

Disable Firefox's Native JSON Viewer

Firefox has a built-in JSON viewer that can prevent this add-on from taking over JSON pages. Disable it first:

1. Open a new tab and go to about:config
2. Accept the warning prompt if shown
3. Search for devtools.jsonview.enabled
4. Set it to false
5. Reload any JSON page

Usage

Navigate to any URL that returns JSON (e.g. https://jsonplaceholder.typicode.com/users). The extension automatically detects JSON responses and replaces the page with an interactive viewer.

• Level buttons (1, 2, 3... All) — collapse/expand the tree to a specific depth
• View picker (Tree / Table / Formatted / Raw / Schema) — switch between interactive tree, sortable table (enabled when the root is an array of objects), pretty-printed JSON, raw JSON, and an inferred JSON Schema
• Query (ƒ or Q) — run a JMESPath expression, e.g. items[?price > \10`].name`; the result replaces the tree, ✕ on the chip restores the document
• Search (⌕ or ⌘F) — find keys, values, and paths; Enter / Shift+Enter step through matches. In table view, search filters the rows and shows a row count instead
• Theme toggle — cycle the theme mode between auto (◐), dark (☾), and light (☀)
• Copy JSON (C) — copy what the active view shows
• Click any line — pins the JSON path in the toolbar, click Copy to copy it
• Keyboard — 1–8 set tree depth, 0 expands all, C copies, Q queries, ⌘F searches
• Console — enable Settings (⚙) → "Expose payload as window.data" (off by default) to make the parsed JSON available as window.data
• Settings (⚙) — pick your dark/light schemes and add custom themes (see Theming)

Privacy note: the window.data convenience is off by default. When you turn it on in Settings, the parsed payload is exposed to the page's main-world JavaScript (including any other extensions running there) on the page's own origin. Once read, JSON Bonsai removes the in-page copy from the DOM. Leave the toggle off if you view authenticated API responses on origins that also run scripts.

Theming

JSON Bonsai uses base16 color schemes for syntax highlighting and the UI.

Mode

The toolbar theme button cycles the theme mode:

• ◐ Auto — follows your operating system's light/dark setting
• ☾ Dark — always dark
• ☀ Light — always light

You pair one dark scheme and one light scheme in the settings menu (⚙). In auto mode, the viewer switches between that pair as your OS flips between light and dark.

Bundled schemes

13 schemes ship with the extension:

• Dark: Catppuccin Mocha (default), Dracula, Nord, Gruvbox Dark, Solarized Dark, OneDark, Tokyo Night Dark, GitHub Dark, Monokai
• Light: Catppuccin Latte (default), Gruvbox Light, Solarized Light, GitHub Light

Custom themes

You can add any base16 scheme of your own:

1. Open the settings menu (⚙) and choose Add theme
2. Paste a base16 scheme as published in the tinted-theming/schemes repo (YAML) — JSON is also accepted
3. The theme is added to your scheme lists, ready to pair with a mode

Invalid pastes show an inline error. Custom themes can be deleted from the settings menu; deleting one that's currently in use reverts to the default scheme.

There are ~290 more ready-made schemes at tinted-theming/schemes (also linked from the settings menu).

Development

npm run dev       # watch mode — rebuilds on file changes
npm run build     # production build
npm run typecheck # TypeScript, no emit
npm test          # unit tests (vitest)
npm run test:e2e  # browser tests (Playwright — loads the built extension into Chromium)
npm run zip       # build and create json-bonsai.zip
npm run package   # build and create per-store zips (Chrome + Firefox)

test:e2e needs a build first and a one-time npx playwright install chromium. CI runs typecheck, unit tests, build, and the E2E suite on every PR.

Releases are manual: run npm run package to build the Chrome and Firefox zip files, then attach them to a GitHub Release and submit them to the browser stores.

After making changes, reload the extension in your browser.

Credits

JSON Bonsai started as a fork of JSON Alexander by Wes Bos and remains MIT licensed — see LICENSE.

It has since been largely rewritten. Of the four original source files only the ~15-line page bootstrap is unchanged; the viewer and content scripts were rebuilt and roughly tripled in size. Virtualized rendering, the Table and Schema views, the JMESPath query bar, web-worker search, lossless big numbers, base16 theming, per-site memory, the build scripts, and the test suite are all new. Thanks to Wes Bos for the original viewer this grew out of.