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● Developer Tools

JSON Formatter & Validator

Transform messy, minified JSON strings into clean, readable code. This tool creates a structured tree view of your data, fixes indentation, validates syntax errors (like missing commas or quotes), and helps you make sense of complex API responses.

Your text never leaves your browser. Everything is processed locally.

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JSON Formatter

Format, validate, and beautify JSON data

JSON JSON
How this tool works Documentation & SEO

Transform messy, minified JSON strings into clean, readable code. This tool creates a structured tree view of your data, fixes indentation, validates syntax errors (like missing commas or quotes), and helps you make sense of complex API responses.

Format, validate, and beautify JSON code. Fix indentation and syntax errors in JSON objects online. Developer-friendly JSON viewer.

Backend Developers debugging API responses
Data Analysts reviewing JSON exports
Frontend Devs mocking state objects
Configuration Managers editing config.json
Students learning data structures
Key features
  • Syntax Validation (detects errors)
  • Auto-indentation (2 or 4 spaces)
  • Collapsible/Expandable tree view
  • Color-coded syntax highlighting
  • Click-to-copy functionality
  • Handles massive JSON payloads
Frequently Asked Questions FAQ
Can it fix bad JSON?
It will validate and point out the error (e.g., 'Expected string at line 5'). It intentionally does not 'auto-fix' logic to prevent data corruption, but it prettifies the structure so you can spot the fix easily.
Is my data sent to a server?
No. This runs entirely in your browser using JavaScript. You can safely format sensitive config files or private data without it leaving your machine.
How do I make it smaller again?
Use our 'JSON Compact' tool to minify it back to a single line for production use.