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JSON Studio
Edit, format, search, diff, validate and transform JSON with Schema + CSV/YAML/TOON conversion all in your browser.
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A full-featured workspace for reading, editing, and validating JSON locally.
JSON Editor Pro is an in-browser workspace for working with JSON documents. Paste API responses, config files, or test fixtures and inspect them as a collapsible tree, pretty-printed text, a side-by-side diff, schema-validated output, or converted formats — without sending data to a server.
JSON (JavaScript Object Notation) is the most common interchange format for web APIs and application configuration. Real payloads are often minified, deeply nested, or slightly invalid. This editor helps you format, find keys, compare versions, validate against a schema, and auto-fix common syntax errors in one place.
Everything runs in your browser. That matters when you handle production configs, customer data, or signed tokens — nothing is uploaded. See our guide on safe local JSON editing for a practical workflow.
Everything you need to know, one click away.
Browse your JSON as a collapsible tree. Click any node to select it — its full path appears in the breadcrumb at the top of the pane.
Ctrl/⌘ + T
Pretty-printed JSON appears on the right, ready to edit. Hit Minify to collapse it to one line, or toggle it off to expand again.
.json file.Ctrl/⌘ + S · minify: Ctrl/⌘ + Shift + M
When JSON fails to parse, an Auto-fix button appears in the status bar. One click runs a local repair pass and replaces the input with corrected JSON when possible.
// and /* */ comments; maps
undefined, NaN, and Infinity to null.{ / [ brackets; can extract JSON
wrapped in JS assignments like const data = ….Always review the result before exporting — deeply broken payloads may still need manual editing.
Paste a second JSON on the right ("B") and see exactly what changed from your input ("A"). Added, removed, and modified values are highlighted inline.
Ctrl/⌘ + D
Write or paste a JSON Schema on the right. Every violation in your input is reported instantly as a clickable error row — click it to jump straight to the problem line.
Ctrl/⌘ + E
Convert your JSON to another format instantly. Pick the target from the toolbar chip and the output updates as you type.
Ctrl/⌘ + Shift + R
Start typing in the search bar to find any key or value across your entire JSON. Use the arrow buttons (or Enter / Shift+Enter) to step through every match.
Ctrl/⌘ + F
.json or .txt file, or drag and drop it
onto the editor..json file.| Ctrl/⌘ + T | Tree mode |
| Ctrl/⌘ + S | Format mode |
| Ctrl/⌘ + Shift + M | Toggle Minify |
| Ctrl/⌘ + D | Diff mode |
| Ctrl/⌘ + E | Schema mode |
| Ctrl/⌘ + Shift + R | Transform mode |
| Ctrl/⌘ + F | Search |
| Enter / Shift+Enter | Next / previous match |
Everything JSON Editor Pro can do — all processed locally in your browser.
Explore and edit your JSON visually. Click any node to select it — its full path appears in the breadcrumb. Inline edits round-trip back to the code editor in real time.
Pretty-print with consistent 2-space indentation or collapse to a single compact line. The output pane is fully editable — make changes directly there without touching the input.
Compare any two JSON documents. Recursive key sorting removes noise from key-order differences so you see only real structural changes. Each side can be formatted or minified independently.
Validate your JSON live against any JSON Schema using AJV. Supports Draft-07, Draft 2019-09, and Draft 2020-12. Errors appear as red squiggles on the input and clickable rows in the error list.
Convert JSON on the fly. CSV follows RFC 4180; YAML is block-style 1.2; TOON is a compact token-oriented notation with indentation-based nesting. Copy or download any result.
One-click repair for common paste-and-copy mistakes — trailing commas, comments, unquoted keys, single-quoted strings, unclosed brackets, and JS-style wrappers. Appears in the status bar whenever JSON fails to parse.
Search across all keys and values simultaneously. In tree mode, ancestor nodes auto-expand so every match is visible. Navigate hits with the arrow buttons or Enter / Shift+Enter.
All parsing, validation, and conversion happen entirely in your browser. Nothing is uploaded. Once the page is loaded, no network connection is required to work with your data.
Open a .json file from disk, drag & drop it onto the editor, or fetch JSON from any
CORS-enabled URL. Export the input as a file or download the transformed output directly.
Common questions about JSON Editor Pro. Click a question to expand.
Yes, completely. All processing — parsing, formatting, diffing, schema validation, and transformation —
happens entirely inside your browser. Your data is never sent to any server, never stored in the cloud,
and never shared. The only persistence is your own browser's localStorage, which you can
clear at any time.
Yes. Once the page has been loaded and the editor assets are cached, all features work without a network connection. The Monaco editor, AJV validator, and all transform logic run locally. The only time the network is used is to load CDN assets on the very first visit, and optionally when using "Load from URL".
Auto-fix handles many common non-standard JSON issues: trailing and missing commas, duplicate commas,
single-quoted strings, unquoted keys, // and block comments, JavaScript literals like
undefined, unclosed { / [ brackets, and text wrapped in assignments
such as const config = …. It runs entirely in your browser. If repair fails, the error
message in the status bar still points to the line that needs manual attention.
The editor handles files up to several megabytes comfortably. Above 1 MB, some features like code folding are automatically disabled to keep the editor responsive. For very large files (10 MB+) you may notice slower tree rendering, but formatting, diff, and transform continue to work.
Draft-07 (default), Draft 2019-09, and Draft 2020-12 — all via AJV. The dialect is auto-detected from the
$schema field in your schema document, but you can override it with the dialect chip in the
Schema pane. An "Infer from input" button generates a starter schema from your current JSON automatically.
TOON (Token-Oriented Object Notation) is an experimental
data serialization format designed to be more compact, token-efficient,
and easier for AI systems and humans to process compared to traditional
formats like JSON.
Traditional formats such as JSON contain a lot of structural punctuation
like braces, commas, and quotation marks. TOON-style formats attempt to
reduce this syntactic overhead while preserving structured data.
Large Language Models (LLMs) process text as tokens. JSON can become
verbose because of repeated punctuation and quoted keys. TOON-style
formats aim to reduce token usage, making prompts and structured data
more compact for AI workflows.
Reduces unnecessary syntax to save prompt space and improve AI
context efficiency.
Minimizes clutter from braces, commas, and quotation marks.
Some implementations aim for deterministic parsing and lightweight
streaming support.
Optimized for agent memory, prompt engineering, and structured AI
communication.
TOON is not currently a universally standardized format. Different
implementations may use different syntax rules and parsing strategies.
When working with TOON, it is important to define or reference the
specific grammar being used.
TOON (Token-Oriented Object Notation)
Core Idea
JSON Example
{
"name": "John",
"age": 25,
"skills": ["JS", "Python"]
}
TOON-style Example
name: John
age: 25
skills[
JS
Python
]Why “Token-Oriented”?
Main Goals
Lower Token Usage
Better Readability
Faster Parsing
AI-Friendly Structure
TOON vs JSON
Feature
JSON
TOON-style
Standardized
Yes
Usually Experimental
Verbosity
Higher
Lower
LLM Efficiency
Moderate
High
Browser Support
Native
Limited
Human Readability
Good
Often Better
Ecosystem
Massive
Small / Emerging
Important Note
Related Formats
Potential Use Cases
Yes. Switch to Diff mode (Ctrl/⌘+D) and use the Sort button on each side. Sorting recursively normalises both object-key order and array element order before comparing, so two semantically identical JSONs with shuffled keys will show zero differences.