JSON Formatter & Validator — Format, Beautify and Validate JSON Online
Working with JSON daily means you inevitably encounter minified API responses, inconsistent indentation from different team members, deeply nested payloads that are impossible to scan, and cryptic parse errors that point to "position 4827" with no line reference.
A dedicated formatter solves these issues in seconds. Paste the raw JSON, get readable output with proper indentation and syntax highlighting, and instantly see if the structure is valid — with exact line and column numbers when it isn't.
This is a client-side JSON formatter, validator and explorer. It parses your JSON using the browser's native JSON.parse(), formats it with configurable indentation, and adds syntax highlighting for readability. Beyond formatting, it provides a collapsible tree view for navigating complex structures.
Everything runs in your browser. After the page loads, zero network requests are made. Your data stays on your machine — always.
Paste or type your raw JSON into the input pane. Auto-format triggers on paste for instant results.
Click Format to beautify with your chosen indentation, or Minify to compress to a single line.
Copy the result, download as a file, or explore the structure with tree view.
Indent with 2 spaces, 4 spaces or tabs. Auto-formats on paste for instant readable output.
Strict RFC 8259 validation with precise error location — line number, column, and highlighted error line.
Interactive collapsible tree with color-coded types. Click any value to copy it to clipboard.
Compress JSON to single-line output. Perfect for config files, API payloads and storage.
Zero network requests after page load. All processing in JavaScript — your data never leaves the browser.
| Feature | This Tool | Premium Editors | Other Free Tools |
|---|---|---|---|
| Formatting & beautification | ✓ | ✓ | ✓ |
| Validation with line/column | ✓ | ✓ | Partial |
| Tree view | ✓ | ✓ | ✗ |
| 100% client-side | ✓ | ✗ | Varies |
| No signup required | ✓ | ✗ | ✓ |
| Free | ✓ | ✗ | ✓ |
This tool conforms to the following specifications:
RFC 8259 — The JavaScript Object Notation (JSON) Data Interchange Format (IETF, December 2017)
ECMA-404 — The JSON Data Interchange Syntax (Ecma International, 2nd Edition)
Disclaimer. This tool is provided "as is" for convenience. While it follows the JSON specification strictly, it is not a substitute for automated testing in your CI/CD pipeline. Always validate critical data with your own test suite. No data is collected, stored, or transmitted.
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JSON.parse() converts a JSON string into a JavaScript object. JSON.stringify() converts a JavaScript object back into a JSON string with optional formatting. This tool uses both: parse to validate your input, and stringify with indentation to produce formatted output.
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