NeatJSON — Viewer & Formatter

About

Raw JSON endpoints — instantly transformed into a beautiful, interactive tree. Zero telemetry. 100% local.
NeatJSON automatically detects and beautifies any raw JSON in your browser with syntax highlighting, collapsible nodes, real-time search, JSON path copying, and 5 themes — all parsed off the main thread so even 10MB files load without freezing your tab.

The Problem: Raw JSON Is Unreadable and DevTools Isn't Enough
You hit a JSON API endpoint in your browser. You get a wall of unformatted text — no line breaks, no indentation, no color, no structure. You can't collapse nested objects, you can't search across keys and values, you can't copy a specific JSON path, and you can't tell where one object ends and another begins.
DevTools helps, but it requires opening a panel, navigating to the Network tab, finding the request, and clicking through multiple layers. It's not designed for quickly reading and navigating JSON responses inline. And most existing JSON formatter extensions are bloated, phone home to external servers, or freeze your tab on large payloads.

The Solution: NeatJSON — The JSON Viewer Built to Developer Standards
NeatJSON detects any raw JSON response automatically — via content-type header and body heuristics — and replaces it with a fully interactive, syntax-highlighted, collapsible tree viewer, rendered entirely inside a Shadow DOM so it never touches the host page. All parsing happens in a Web Worker off the main thread. Everything runs locally. Nothing leaves your browser.

✨ Why Developers Choose NeatJSON
🌳 Auto-Detection & Instant Tree Rendering
Navigate to any raw JSON endpoint or open any .json file and NeatJSON activates automatically — no clicking, no triggering required. The plain-text dump is replaced instantly with a fully structured, syntax-highlighted collapsible tree. Supports JSONP stripping for legacy endpoints.
⚡ Web Worker Parsing — Zero UI Freeze, Even on 10MB Files
JSON parsing runs entirely off the main thread in a dedicated Web Worker. Your tab stays fully responsive during parsing regardless of payload size. No spinners, no frozen tabs, no dropped frames — even on the largest API responses you'll encounter in real development.
🔍 Real-Time Search — Find Anything Across the Entire Tree
Type any key or value and NeatJSON searches the entire JSON structure in real time, automatically expanding collapsed nodes that contain matches so results are always visible in context. No manual expanding required to find what you're looking for.
🔗 JSON Path Copy — Know Exactly Where You Are in the Structure
Hover any node and click the link icon to copy its full JSON path to clipboard (e.g. $.users[0].email). Essential for writing queries, debugging nested structures, or communicating exact data locations with teammates.
📋 One-Click Value Copy — Any Primitive, Instantly
Hover any string, number, boolean, or null value and click the copy icon to grab it to clipboard. No selecting, no triple-clicking, no accidental partial copies.
🔗 Clickable URLs & Unix Timestamp Hints
String values that are URLs automatically become clickable links opening in a new tab. 10 and 13-digit numeric strings display their ISO date equivalent inline — no mental conversion required when reading timestamps.
🎨 5 Professional Themes — Dark, Light & Everything Between
Choose from Dark (Catppuccin), Light, Monokai, Solarized Dark, and Nord. Each theme applies distinct, carefully chosen colors to keys, strings, numbers, booleans, nulls, and URLs — making deeply nested structures scannable at a glance.
🧩 Shadow DOM Isolation — Zero Page Conflicts, Ever
NeatJSON's entire viewer is rendered inside an isolated Shadow DOM. Its styles never bleed into the host page and the host page's CSS never corrupts the viewer — guaranteed compatibility with every JSON endpoint regardless of what styles the server returns.
⚙️ Full Control: Indent, Depth, Expand, Collapse, Download
Choose indent size (2, 4, 8 spaces, or tab), set auto-collapse depth, expand or collapse the entire tree with toolbar buttons, toggle between formatted tree and indented raw text, and download the formatted JSON as a .json file — one click each.
📊 Info Bar — File Size, Depth, Root Type at a Glance
The info bar shows root type, top-level key count, nesting depth, and file size for every JSON response — instant structural context without reading a single line.

🔒 Privacy-First. Zero Telemetry. 100% Local.

No account or sign-up required.
Zero external network requests — ever.
No JSON content, endpoints, or URLs are transmitted anywhere.
All parsing, rendering, and searching happens locally in your browser.
No analytics, telemetry, or third-party tracking of any kind.


🙋 Perfect For:

Frontend and backend developers inspecting API responses daily
DevOps and platform engineers reading configuration and service JSON
QA engineers validating API payloads during testing
Data engineers exploring JSON data structures from pipelines and exports
Anyone who regularly visits raw JSON endpoints and deserves a better experience


📥 Install NeatJSON and Never Read Raw JSON Again.
Navigate to any JSON endpoint. NeatJSON handles the rest — automatically, instantly, locally.