What happens if my JSON is invalid?

The tool will display a validation error with the line number and description of the issue. Common errors include missing commas, unclosed brackets, or trailing commas. Fix the error and try formatting again.

Can I format very large JSON files?

The tool can handle JSON files up to about 10MB in your browser. For larger files, the browser may become slow or crash. For files over 10MB, use desktop JSON editors like VS Code with JSON extensions or specialized JSON tools.

Does formatting change my JSON data?

No, formatting only changes whitespace and indentation—it doesn't modify the actual data. Minifying removes whitespace but preserves all data. The formatted JSON is functionally identical to the original.

What's the difference between format and minify?

Format adds indentation and line breaks to make JSON readable. Minify removes all whitespace to reduce file size. Use format for debugging and readability. Use minify for production to reduce file size.

Can I format JSON with comments?

Standard JSON doesn't support comments. If your JSON has comments (like JSONC or JSON5), they will cause validation errors. Remove comments first, or use a JSON5 formatter that supports comments.

Can I format JSON with nested objects and arrays?

Yes. The formatter handles deeply nested JSON structures of any complexity, including nested objects, arrays, arrays of objects, and mixed types. It properly indents each nesting level and supports collapsible sections for easier navigation of large JSON documents.

What happens if my JSON has syntax errors?

The tool validates JSON syntax as you type or paste. If errors are found, it highlights the exact line and position of the error with a descriptive message (e.g., 'Unexpected token at line 15, column 8'). This makes it easy to find and fix missing commas, brackets, or quotes.

Can I minify formatted JSON?

Yes. The tool supports both formatting (beautifying) and minifying JSON. Minification removes all whitespace, indentation, and line breaks, producing the most compact JSON string possible. This is useful for reducing payload sizes in API responses and configuration files.

JSON Formatter - Validate & Beautify Free

When to Use This Tool

Use this when:

You receive minified JSON from an API and need to read or debug it
You need to validate JSON syntax before using it in your code
You want to format JSON config files for better readability (package.json, tsconfig.json)
You're debugging API responses and need to see the structure clearly
You need to minify JSON to reduce file size for production
You're learning JSON and want to see properly formatted examples
You need to convert between formatted and minified JSON

Don't use this if:

You need to edit JSON with advanced features like schema validation or transformation (use JSON editors)
You're working with JSON files larger than 10MB (use desktop JSON editors)
You need to merge or compare multiple JSON files (use specialized tools)
You require JSON schema validation or type checking (use JSON Schema validators)

What is a JSON Formatter?

A JSON formatter (also called a JSON beautifier or JSON pretty printer) takes raw, minified, or messy JSON data and reformats it with proper indentation, line breaks, and syntax highlighting for easy reading. Our tool also validates JSON syntax, highlighting errors with line numbers. All processing happens in your browser — your data is never sent to any server.

JSON formatting is a daily task for software developers, API engineers, and data analysts. Minified JSON from API responses, configuration files, and databases is virtually unreadable without proper formatting. Syntax errors in JSON can break applications, making validation equally important.

This tool is essential for API developers debugging response payloads, back-end engineers editing configuration files, data analysts exploring JSON datasets, DevOps engineers reviewing infrastructure-as-code templates, and QA testers validating API outputs.

Compared to browser developer tools (limited formatting, no editing), command-line tools like jq (require installation and learning curve), or online formatters like JSONLint (which may log your data), PureXio provides instant formatting with syntax highlighting, tree view navigation, error detection with precise line numbers, and the ability to minify formatted JSON back to a compact form.

The tool supports configurable indentation (2 or 4 spaces, tabs), collapsible sections for large objects, and handles JSON files up to several megabytes in size.

Best for: formatting, validating, and beautifying JSON data. Syntax highlighting, error detection, tree view. Handles large files. 100% private.

How to Format JSON

Paste your JSON (minified or formatted) into the input field

Choose indentation (2, 4, or 8 spaces) and click 'Format' to beautify, or 'Minify' to compress

Copy the formatted or minified JSON, or download it as a file

Common Use Cases

Format a minified API response (500KB) to debug why a field is missing

Beautify a package.json file with 2-space indentation for better readability

Minify a 50KB config.json file to 30KB for faster loading in production

Validate JSON syntax before pasting it into your code editor (check 500-line API response for errors)

Format nested JSON objects with 4-space indentation to understand the structure

Convert a single-line JSON string (2000+ characters) into formatted, readable code with 2-space indentation

Format JSON from a database export (10,000 records) to review the data structure and values

Features

Format minified JSON into readable, indented code

Validate JSON syntax and highlight errors with line numbers

Customizable indentation: 2, 4, or 8 spaces

Minify JSON to reduce file size (removes whitespace)

Real-time validation as you type

100% private—all processing happens in your browser

No file size limits (limited by browser memory, typically 10MB)

Limitations & Constraints

Maximum file size: ~10MB (browser memory limit). For larger files, use desktop JSON editors.

JSON with comments (JSONC/JSON5) will show validation errors. Remove comments or use JSON5 formatters.

Very deeply nested JSON (50+ levels) may cause browser slowdowns. Consider flattening the structure.

Circular references in JSON objects cannot be formatted (JSON doesn't support circular references).

Non-standard JSON extensions (like trailing commas in older JSON) may not validate correctly.

Troubleshooting

JSON validation fails but the JSON looks correct

Solution: Check for common issues: trailing commas after the last item in arrays/objects, missing quotes around keys, or unclosed brackets/braces. Copy the error message and check the line number mentioned. Use a JSON linter for detailed error analysis. Prevention: Always validate JSON before using it in production code.

Browser becomes slow or crashes when formatting large JSON

Solution: Large JSON files (over 5MB) can cause browser performance issues. Try formatting in smaller chunks, or use desktop software like VS Code with JSON extensions. Close other browser tabs to free up memory. Prevention: Keep JSON files under 5MB for browser-based formatting.

Formatted JSON doesn't match expected indentation style

Solution: Select your preferred indentation (2, 4, or 8 spaces) before clicking Format. The tool uses the selected indentation consistently. If you need tabs instead of spaces, use a desktop JSON editor. Prevention: Choose your indentation preference before formatting.

Minified JSON is still too large

Solution: Minifying only removes whitespace—it doesn't compress data. For further size reduction, consider removing unnecessary fields, using shorter key names, or compressing the JSON file with gzip. For production APIs, enable gzip compression on the server. Prevention: Design JSON structures to be minimal from the start.

JSON has special characters that break formatting

Solution: Ensure special characters in strings are properly escaped (\", \\, \n, etc.). Unicode characters should be valid. If JSON contains binary data, consider encoding it as Base64 first. Check that all strings are properly quoted. Prevention: Always escape special characters when creating JSON manually.