Hi! Describe any JSON structure and I'll generate it instantly.
Try: "A product with variants, pricing and stock"
✦
Create a new file or load one to begin
Source
Tree
Changes
Stats
JSON Editor Studio — Free JSON Formatter, Validator & Optimiser
Edit, format, validate, and optimise JSON directly in your browser for free. No sign-up. No data sent to any server. Your JSON stays private on your device.
Features
Real-time JSON validation with clear inline error messages
JSON formatter — prettify and indent JSON with one click
JSON minifier — compress JSON to a single line
Interactive tree view — explore nested JSON structures visually
JSON optimiser — remove nulls, empty strings, empty arrays and objects; deduplicate arrays; sort keys alphabetically; trim whitespace
Multiple file management with automatic browser localStorage — files persist across sessions
6 built-in colour themes: Midnight, Arctic, Mocha, Forest, Dusk, Paper
Keyboard shortcuts: Ctrl+S to save, Ctrl+N for new file
Filter and search keys and values in the tree view
JSON statistics: key count, depth, type breakdown
Download JSON files or copy to clipboard
Load JSON files from your local device
How to use the JSON Editor
Paste or type your JSON into the source editor. The tool validates your JSON in real time. Click Format to prettify it, Minify to compress it, or Optimise to clean it up. Use the Tree tab to explore your JSON structure interactively.
Is my JSON data safe?
Yes. All processing happens entirely in your browser using JavaScript. No data is sent to any server. Your JSON is stored only in your browser's localStorage for session persistence.
Frequently Asked Questions
How do I format JSON online?
Paste your JSON into the editor and click the Format button. It will be prettified and indented instantly.
How do I validate JSON?
Just type or paste your JSON. The status bar shows a green tick for valid JSON or a red error with the exact parse problem for invalid JSON.
What is a JSON tree view?
A tree view displays your JSON as a collapsible hierarchy, making it easy to explore deeply nested objects and arrays without reading raw text.
What does the JSON optimiser do?
It removes null values, empty strings, empty arrays and objects, deduplicates array entries, sorts keys alphabetically, trims whitespace from strings, and unwraps single-item arrays — all individually configurable.
Does this JSON editor work offline?
Yes. Once the page is loaded, the editor works entirely offline. No internet connection is needed to format, validate, or optimise your JSON.
New file
Give your JSON file a name to get started.
JSON Schema Generator & Validator
Options:
Input JSON
Generated Schema
Generated schema will appear here.
JSON Schema
Paste a schema and JSON, then click Validate
JSON to Validate
JSON Schema Input
Schema Explorer
Paste a schema on the left to explore it.
JSON Diff Editor
Removed
Added
Changed (old)
Changed (new)
A
JSON A — Original
B
JSON B — Modified
A Original
B Modified
JSON Editor — Documentation
Overview
JSON Editor Studio is a fully browser-based JSON editing tool — no sign-up, no server, no data leaving your device. Everything runs locally.
📁
File management
Create, save, rename and switch between multiple JSON files
✏️
Editing JSON
Live validation, formatting, minification and copy/download
🌲
Tree view
Explore JSON structure visually with collapsible nodes and search
⚡
Optimiser
Remove nulls, deduplicate arrays, sort keys and trim strings
🤖
AI Generator
Describe any JSON and have it generated instantly using AI
🎨
Themes
Six built-in colour themes — light, dark and everything between
🔒
Storage & Privacy
Auto-save, encrypted API key storage and localStorage management
⌨️
Shortcuts
Keyboard shortcuts to speed up your workflow
ℹ️All processing happens in your browser. No JSON data is ever sent to any server.
Quick start
Get up and running in under a minute.
Option A — Paste existing JSON
Click New in the toolbar to create a fresh file, or just start typing in the source pane.
Paste your JSON into the left source pane. The status bar instantly shows ✓ Valid JSON or the exact error.
Click Format to prettify with proper indentation, or Minify to collapse it.
Explore the structure in the Tree tab on the right. Click ▶/▼ to expand or collapse nodes.
Save with Ctrl+S (or Cmd+S on Mac). Your file is auto-saved to localStorage.
Option B — Generate JSON with AI
Click AI Generate in the toolbar. A chat popup appears in the bottom-right corner.
Choose Pollinations AI (free, no key needed) or switch to ChatGPT/Gemini if you have a key.
Type your description — e.g. "A product with variants, pricing and stock levels" — and press Enter.
Click "Use in editor" on the response. A new file is created and opened automatically.
💡Use the quick chips (👤 User profile, 🛍 Product…) in the AI chat for one-click prompts.
File management
Work with multiple JSON files simultaneously. All files persist in your browser's localStorage.
Creating files
Click New in the toolbar (or press CtrlN) to name and create a blank file.
Click the + button at the top of the sidebar for a quick new file.
Use Load file to open a .json file from your device — it appears as a new entry in the sidebar.
Files generated by AI are automatically created as new files with auto-derived names.
Switching files
Click any file in the left sidebar to switch to it.
Files are auto-saved silently when you switch — no popup, no interruption.
An amber dot on the file tab or sidebar item means the file has unsaved manual changes.
Saving
Press CtrlS (or CmdS) or click Save to explicitly save.
Content is also auto-persisted to localStorage on every keystroke — so nothing is lost even if the tab crashes.
The file tab shows the last saved time when saved manually.
Renaming
Click the filename in the file tab bar (above the editor) and type a new name. Press Enter or click away to confirm. The .json extension is added automatically if omitted.
Deleting files
Hover over a file in the sidebar and click the × button that appears.
Or click the trash icon in the top-right of the toolbar to delete the currently open file.
⚠️Deleting a file removes it from localStorage immediately and cannot be undone.
Downloading
Click Download to save the current file to your device as a .json file with the file's current name.
Editing JSON
The source pane on the left is a plain-text editor. Type or paste any JSON and get instant feedback.
Real-time validation
As you type, the status bar at the bottom updates instantly:
✓ Valid JSON — shows key count and file size.
✗ Error — shows the exact parse error message (e.g. "Unexpected token } at position 42") so you can fix it immediately.
Format (Prettify)
Click Format or press CtrlShiftF to reformat the JSON with 2-space indentation. This also re-validates the content.
{"name":"Alice","age":30}
↓ After Format
{
"name": "Alice",
"age": 30
}
Minify
Click Minify to strip all whitespace and collapse the JSON to a single line — ideal for production payloads.
Copy
Click Copy to copy the entire source to your clipboard. A brief toast confirms the copy.
Stats tab
Switch to the Stats tab in the right panel to see a breakdown: total keys, max depth, count of strings, numbers, booleans, nulls, objects, and arrays.
Tree view
The Tree tab in the right panel shows your JSON as a live, collapsible hierarchy.
Navigation
Click ▼ to collapse a node, ▶ to expand it.
Collapsed nodes show a count summary — e.g. {3} for an object with 3 keys, [5] for an array with 5 items.
The tree updates in real time as you type in the source pane.
Syntax colours
Blue — object keys
Green — string values
Amber — number values
Pink — boolean values (true/false)
Grey italic — null values
Search and filter
Type in the filter bar above the tree to instantly highlight matching keys or values. The tree hides non-matching branches so you can focus on what you're looking for. Matching text is highlighted in amber.
💡Search is case-insensitive. It matches both keys and values at any depth.
Changes tab
After running the Optimiser, switch to the Changes tab to see a detailed list of every modification made — which keys were removed, which arrays were deduped, and which strings were trimmed.
Format & Minify
Instantly beautify or compress your JSON with a single click.
Format (Prettify)
Reformats your JSON with consistent 2-space indentation, making it human-readable. Invalid JSON cannot be formatted — fix any errors shown in the status bar first.
When to use
When you receive minified JSON from an API and need to read it
Before committing JSON config files to source control
To normalise inconsistent indentation across a team
Minify
Removes all whitespace (spaces, newlines, tabs) to produce the most compact valid JSON string. Reduces file size significantly for large JSON.
When to use
Before embedding JSON in HTTP request bodies
When optimising payload size for APIs
For environment variables or config that should stay compact
💡Both operations preserve the exact data — only whitespace changes. Values, keys, and types are untouched.
Optimiser
Clean up and reduce your JSON by removing unwanted values, sorting keys, and more — with full control over what changes.
Click Optimise in the toolbar to expand the options panel. Select which rules to apply, then click Apply optimisations or Preview first to see the changes without modifying your JSON.
Available rules
Remove nulls — deletes any key whose value is null. Useful for cleaning API responses.
Remove empty strings — deletes keys with a value of "".
Remove empty arrays — deletes keys with a value of [].
Remove empty objects — deletes keys with a value of {}.
Deduplicate arrays — removes duplicate primitive values from arrays (strings, numbers, booleans). Objects within arrays are not touched.
Sort keys A–Z — recursively sorts all object keys alphabetically. Great for normalising JSON configs.
Trim strings — strips leading and trailing whitespace from all string values.
Flatten single arrays — if an array contains exactly one primitive item, unwraps it to just the value.
Preview mode
Click Preview to run the optimiser without applying changes. The Changes tab shows exactly what would be modified. Click Apply to commit.
Size savings badge
After optimising, a badge shows the size reduction (e.g. −1.2 KB (18%)) or increase if the changes made the JSON larger.
⚠️Optimisation is destructive — removed keys cannot be recovered. Use Preview first, and keep a backup via Download if needed.
AI Generator
Describe any JSON structure in plain English and have it generated instantly. Click AI Generate in the toolbar to open the chat popup.
Providers
Pollinations AIFREE — No API key required. Works immediately. Uses OpenAI-compatible models via the Pollinations API. Models: openai, openai-large, mistral, llama.
ChatGPT — Requires an OpenAI API key (get one here). Models: GPT-4o, GPT-4o mini, GPT-4 Turbo, GPT-3.5 Turbo.
GeminiFREE KEY — Google offers a free tier. Get a key at Google AI Studio (no credit card). Models: Gemini 2.0 Flash, 1.5 Pro, 1.5 Flash.
How to generate
Open the chat by clicking AI Generate in the toolbar.
Select your provider using the tabs at the top of the popup. For ChatGPT or Gemini, enter your API key in the bar that appears.
Type your prompt in the input at the bottom, e.g. "A restaurant menu with sections, items, prices and dietary tags".
Press Enter or click the send button. The AI generates the JSON and shows a preview in the chat.
Click "Use in editor" to open the generated JSON as a new file.
Quick chips
Click the suggestion chips (👤 User profile, 🛍 Product, 📄 API response, ⚙️ App config, 🍽 Menu) for one-click example prompts.
API key security
Click the 🔐 lock icon next to the API key input to open the key security modal:
Save encrypted — encrypts your key with AES-256 using your password and stores it in localStorage. Without the password, it's unreadable.
Load encrypted — enter your password to decrypt and load the key into session memory.
Session only — key lives in memory only and is cleared when you close the tab. Never written to localStorage.
ℹ️Your API keys are only ever sent directly to the provider's API (OpenAI, Google). They never pass through any third-party server.
Themes
Six carefully crafted colour themes — pick one that suits your environment and mood.
Click the theme button (next to the trash icon in the toolbar) to open the theme picker. Your choice is saved to localStorage and applied on every future visit.
Available themes
Midnight — Deep dark blue-grey. The default. Easy on the eyes for extended sessions.
Arctic — Clean white light mode. High contrast, minimal.
Mocha — Warm dark theme with amber and brown tones. Cosy and readable.
Forest — Deep green dark theme. Distinctive and easy to spot on a second monitor.
Dusk — Purple-tinted dark mode. Rich and expressive.
Paper — Sepia / parchment light mode. Retro, low-glare.
Every theme updates the background, text, syntax colours in the tree, accent colours, borders, and textarea selection highlight simultaneously.
Storage & Privacy
Everything stays in your browser. Nothing is sent to any server.
What is stored in localStorage
JSON files — all file names, content and saved state (json_editor_files)
Active file — which file was last open (json_editor_active)
Theme — your chosen colour theme (json_editor_theme)
Encrypted API keys — AES-256 encrypted blobs only, never plaintext (json_editor_enc_key_*)
Auto-save behaviour
File content is persisted to localStorage on every keystroke — so edits survive a tab crash.
Switching between files silently saves the current file first.
Closing the browser with unsaved changes shows a native browser confirmation dialog.
Clearing storage
Click the Clear button at the bottom of the file sidebar to wipe all files from localStorage. This is permanent.
API key encryption
API keys (ChatGPT, Gemini) can be stored encrypted using AES-256-GCM via the Web Crypto API:
Password is processed through PBKDF2 with 200,000 iterations and a random salt.
A fresh random IV is generated for every encryption operation.
The encrypted blob in localStorage is meaningless without the password.
Keys can also be kept in session memory only (cleared on tab close, never written to localStorage).
💡Pollinations AI requires no API key at all — use it as the default to avoid key management entirely.
Keyboard shortcuts
Speed up your workflow with keyboard shortcuts. All shortcuts work when the editor is focused.
File operations
CtrlS
Save the current file
CtrlN
Create a new file
Navigation
Esc
Close any open panel, dropdown, or modal
AI chat input
Enter
Send message in the AI chat
ShiftEnter
New line in the AI chat input
Browser-native shortcuts (in the source editor)
CtrlZ
Undo
CtrlY
Redo
CtrlA
Select all
CtrlC
Copy selected text
CtrlX
Cut selected text
Tab
Insert tab / indent
ℹ️On Mac, use Cmd instead of Ctrl for all shortcuts.
About JSON Editor Studio
A free, privacy-first JSON editing tool built for developers — no account, no server, no compromises.
100%
Client-side processing
Free
Forever, no sign-up needed
6
Built-in colour themes
12+
Tools in one editor
Our Mission
JSON Editor Studio was built with one goal: give every developer a powerful, zero-friction JSON toolset that respects their privacy. We believe developer tools should be fast, free and trustworthy. Your data should never leave your device — and with us, it never does.
Everything from editing to formatting, minifying, comparing, generating schemas and AI-powered JSON generation runs entirely in your browser using JavaScript. There is no backend. There are no accounts. There is no data collection.
Privacy Promise
🔒Your JSON data never leaves your device. All processing — formatting, validation, comparison, schema generation — happens locally in your browser. We collect no analytics, no telemetry, and no usage data.
No server-side processing of your JSON
No user accounts or registration required
No cookies beyond what your browser sets locally
No third-party analytics or tracking scripts
API keys are encrypted AES-256 in your own localStorage — we never see them
Files are stored only in your browser's localStorage — on your machine
What's Included
JSON Editor — multi-file editor with localStorage persistence and auto-save
JSON Formatter — prettify with 2-space indentation instantly
JSON Minifier — compress to a single line for APIs
JSON Validator — real-time validation with precise error messages
JSON Tree Viewer — collapsible, searchable hierarchy explorer
JSON Optimiser — remove nulls, deduplicate, sort keys, trim strings
JSON Compare — VS Code-style side-by-side diff with inline highlights
JSON Schema Generator — generate JSON Schema from any JSON sample
JSON Schema Validator — validate JSON against a schema with detailed errors
AI JSON Generator — describe any JSON in plain English; Pollinations AI generates it free
6 Themes — Midnight, Arctic, Mocha, Forest, Dusk, Paper
SEO URL routing — clean paths for every tool
Built for Developers
Whether you're a frontend developer debugging API responses, a backend engineer validating config files, a data engineer inspecting pipeline outputs, or a student learning JSON — this tool is built for you. No fluff, no paywalls, no distractions.
💡JSON Editor Studio works offline too. Once loaded, all tools function without an internet connection (except AI generation).