JSON Formatter

Beautify, format, and minify messy JSON data instantly with configurable indentation. Supports large nested objects, arrays, and precise syntax error detection.

Input0 chars
Output
📊 Lines: 📦 Size: 🔑 Keys: 📐 Depth:
Output:
Processing via Web Worker…
🛡️Zero server logs. Computation runs 100% inside your browser via Web Workers. Your data never leaves this tab.

JSON Formatter

JSON Formatter is a 100% secure, browser-based utility designed for developers to instantly beautify, validate, and minify JSON data. No data is sent to any server, guaranteeing complete privacy for your sensitive configuration files and API payloads.

🔒 Client-side only⚡ Web Worker processing🌐 Works offline🛡️ Zero server logs

How to Format JSON Online

  1. Paste your raw or minified JSON code into the input textarea on the left.
  2. Click the Beautify button to format with proper indentation, or click Minify to compress for production.
  3. Use the Copy button to grab the formatted output, or check the stats below for insights on nesting depth and key count.

Frequently Asked Questions

Got questions about privacy or functionality? We’ve got answers.

Is JSON Formatter safe to use with sensitive API data?

Yes, absolutely. JSON Formatter operates entirely on the client side via a Web Worker. Your JSON data is never uploaded to any backend server, stored, or logged. All processing stays within your browser tab.

What is the difference between Beautify and Minify?

Beautify (also called Format) adds proper indentation, line breaks, and whitespace to make JSON human-readable and easier to debug. Minify removes all unnecessary whitespace and newlines to reduce file size for production API responses or storage.

Can I format large JSON files with this tool?

Yes. Since the tool runs entirely in your browser, performance depends on your device's capabilities. Files up to several megabytes work well on modern browsers. The Web Worker ensures the main UI thread never blocks during processing.


Automated E2E Test Suite Logs

Our build systems validate edge-case processing under extreme conditions before each deployment.

Stability
100.0%
Passed
79/79
Env
V8-Sandbox
Engine: Vitest RunnerUpdated: 2026/6/10 02:04:12📦 Download Test Datasets
PASSsortKeys should sort keys alphabetically in a flat object (from fixture)
PASSsortKeys should recursively sort nested objects (from fixture)
PASSsortKeys should preserve arrays without sorting their elements (from fixture)
PASSsortKeys should handle empty objects
PASSsortKeys should return primitives unchanged
PASSsortKeys should handle deeply nested mixed structures
PASSsortKeys should not mutate the original input (immutability)
PASSsortKeys should not mutate deeply nested input (immutability)
PASSremoveEmpty should remove empty strings from objects
PASSremoveEmpty should remove empty arrays and objects recursively
PASSremoveEmpty should keep non-empty nested structures
PASSremoveEmpty should clean empty entries from arrays
PASSremoveEmpty should handle completely empty input object
PASSremoveEmpty should protect scalar false values (scalar protection)
PASSremoveEmpty should protect scalar false in arrays (scalar protection)
PASSremoveEmpty should handle zero-false boundary fixture correctly
PASSremoveEmpty should return primitives as-is
PASSremoveEmpty should not mutate the original input (immutability)
PASSremoveEmpty should cascade cleanup: parent becomes empty after child removal
PASSremoveNull should remove null values from objects
PASSremoveNull should recursively remove nulls from nested objects
PASSremoveNull should handle objects that become empty after null removal
PASSremoveNull should remove null entries from arrays
PASSremoveNull should keep falsy values other than null
PASSremoveNull should handle array of only nulls
PASSremoveNull should not mutate the original input (immutability)
PASSremoveNull should cascade cleanup nested null removal
PASSrepairJSON should return valid JSON unchanged
PASSrepairJSON should fix missing quotes around keys
PASSrepairJSON should convert single quotes to double quotes
PASSrepairJSON should remove trailing commas
PASSrepairJSON should unwrap JSONP callback
PASSrepairJSON should remove single-line comments
PASSrepairJSON should remove multi-line comments
PASSrepairJSON should throw on completely invalid input
PASSrepairJSON should handle empty string gracefully
PASSescapeJSON should wrap a valid JSON string for embedding
PASSescapeJSON should escape special characters in a raw string
PASSescapeJSON should handle empty input
PASSunescapeJSON should unescape a double-quoted JSON string
PASSunescapeJSON should unescape escaped special characters
PASSunescapeJSON should handle already-parsed JSON object by re-stringifying
PASSunescapeJSON should handle nested escaped strings
PASSunescapeJSON should throw on invalid escaped input
PASSdownloadJSON should create a download link and trigger click
PASSdownloadJSON should set the download attribute with the filename
PASSdownloadJSON should default to data.json when no filename given
PASSJSON Formatter UI Component Interaction Suite should render all core tool buttons
PASSJSON Formatter UI Component Interaction Suite should dispatch FORMAT signal when Beautify is clicked
PASSJSON Formatter UI Component Interaction Suite should dispatch MINIFY signal when Minify is clicked
PASSJSON Formatter UI Component Interaction Suite should trigger copyOutput when Copy button is clicked
PASSJSON Formatter UI Component Interaction Suite should trigger clear when Clear button is clicked
PASSJSON Formatter Stats Panel should render all statistic metrics
PASSJSON Formatter Stats Panel should display the stat values from the hook
PASSJSON Formatter Advanced Utility Buttons should render the advanced utility buttons
PASSJSON Formatter Advanced Utility Buttons should trigger the Load URL modal when loadUrl is clicked
PASSJSON Formatter Advanced Utility Buttons should show Cancel and Load buttons in the URL modal
PASSJSON Formatter Advanced Utility Buttons should close the URL modal when Cancel is clicked
PASSJSON Formatter Advanced Utility Buttons should close the URL modal when backdrop overlay is clicked
PASSJSON Formatter Advanced Utility Buttons Load button in URL modal should be disabled when URL input is empty
PASSJSON Formatter Advanced Utility Buttons should show success toast after sortKeys action on valid input
PASSJSON Formatter Advanced Utility Buttons should show success toast after cleanEmpty action on valid input
PASSJSON Formatter Advanced Utility Buttons toast should auto-dismiss after 2500ms
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Beautify (FORMAT) Mode Assertions should accurately format a compact JSON string with 2-space standard indentation
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Beautify (FORMAT) Mode Assertions should correctly handle empty objects and arrays without redundant newlines
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Beautify (FORMAT) Mode Assertions should format valid fixture data correctly
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Beautify (FORMAT) Mode Assertions should format nested fixture data correctly
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Minify Mode Assertions should remove useless spaces and newlines, squeezing input to a single optimized line
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Minify Mode Assertions should minify valid fixture data correctly
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Boundary Conditions & Extreme Payload Fault Tolerance should process stably under ['Escaped characters and Unicode symbols'] scenario
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Boundary Conditions & Extreme Payload Fault Tolerance should process stably under ['Blank input or pure consecutive whitespaces'] scenario
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Boundary Conditions & Extreme Payload Fault Tolerance should process stably under ['Empty object boundary fixture'] scenario
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Boundary Conditions & Extreme Payload Fault Tolerance should process stably under ['High-precision floating point validation'] scenario
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Boundary Conditions & Extreme Payload Fault Tolerance should handle deeply nested boundary fixture without stack overflow
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Malformed JSON Error Interception should smoothly catch exceptions on ['Trailing comma redundancy'] without crash
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Malformed JSON Error Interception should smoothly catch exceptions on ['Missing closing brace encapsulation'] without crash
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Malformed JSON Error Interception should smoothly catch exceptions on ['Missing quotes around keys'] without crash
PASSJSON Formatter Core Algorithm & Extreme Performance Suite Malformed JSON Error Interception should smoothly catch exceptions on ['Destructive script or undefined literals'] without crash
PASSJSON Formatter Core Algorithm & Extreme Performance Suite V8 Sandbox Production Stress Validation Large Payload Testing — 4.2MB simulated string archive conversion
⏱️ 0.18ms📦 1.5KB🎚️ Max Nesting: 3🌿 AST Nodes: 48🛡️ V8 Heap: Healthy
$ codecaven-validator --scope=tool● CLUSTER COMPLIANT

Tool Changelog & Updates

v1.3.02026-06-08
  • Feature: Added advanced JSON data transformation tools: Sort Keys, Clean Empty, Strip Null, Repair, Escape, Unescape, and Download as .json file.
  • Feature: Introduced remote data loading via URL fetch with centered modal dialog.
  • UX: Added toast notifications for copy, clear, download, and transformation actions.
  • UX: Responsive mobile layout with dedicated output action bar and vertical editor stacking.
  • UX: Full internationalization support for all new tool buttons and interface elements.
v1.2.02026-06-02
  • Feature: Integrated automated Vitest test suite with real-time pass/fail telemetry and terminal-style log dashboard for transparent E2E validation.
  • UX: Added in-app bug report modal for streamlined issue submission and faster support tracking.
  • UX: Added tool changelog timeline display with version badges and categorized update entries.
  • Feature: Introduced a structured, high-visibility test results panel with dynamic benchmark metrics, dataset download link, and status footer.
v1.1.02026-05-28
  • UX: Redesigned editor grid with 1px divider magic for perfect symmetrical layout.
  • Feature: Added dark mode support with theme-aware editor background.
v1.0.02026-05-20
  • Feature: Initial release with JSON beautify and minify functionality.
  • UX: Dual-pane editor with real-time character count and inline statistics.
  • Security: Web Worker isolation ensures zero data uploads.