JSON Format — Free Online Tool

A JSON formatter is a tool that beautifies and structures JSON data by adding proper indentation, line breaks, and spacing for improved readability. Our JSON formatter instantly transforms minified or poorly formatted JSON into clean, readable code with syntax highlighting and error detection. Essential for developers working with APIs, configuration files, and data exchange formats who need to quickly understand and debug JSON structures.

Features

• Syntax Validation: Real-time JSON syntax checking with detailed error messages and line-by-line issue highlighting.
• Customizable Formatting: Configure indentation style, key sorting, and formatting rules to match your coding standards.
• Large File Support: Handle massive JSON files up to several MB with smooth performance and responsive interface.
• Syntax Highlighting: Color-coded JSON elements including strings, numbers, booleans, and null values for easy reading.

Frequently Asked Questions

Can the JSON formatter fix syntax errors?

The formatter identifies and highlights syntax errors but cannot automatically fix them. It provides detailed error messages to help you locate and correct issues manually.

What's the maximum file size the tool can handle?

Our JSON formatter can process files up to 10MB in size, making it suitable for large configuration files, API responses, and data exports.

Does formatting change the JSON data structure?

No, formatting only changes whitespace and indentation. The actual data, keys, values, and structure remain exactly the same.

Can I customize the indentation and formatting style?

Yes, you can choose between 2 or 4 spaces, tabs for indentation, and enable options like alphabetical key sorting and compact arrays.

Does the tool work with JSON5 or JSONC formats?

Currently, our formatter supports standard JSON format. For JSON5 or JSONC (with comments), consider using our specialized configuration formatters.

Can I collapse or expand specific JSON sections?

Yes, the formatted output includes collapsible sections for objects and arrays, allowing you to focus on specific parts of large JSON files.

Is my JSON data sent to servers for processing?

No, all JSON formatting happens client-side in your browser. Your data never leaves your device, ensuring complete privacy and security.

Can the tool sort JSON object keys alphabetically?

Yes, there's an optional setting to sort object keys alphabetically, which is useful for consistent formatting and easier comparison.

What happened to smalldev.tools?

smalldev.tools is no longer available. Prism by SWEDevTools offers the same developer tools and more, with offline support, pipeline chaining, and completely free usage — no signup required.

Is Prism a good alternative to jsonformatter.org?

Yes. Prism offers the same JSON formatting and validation capabilities with full offline support, pipeline chaining, and zero ads. Your data never leaves your browser, unlike most online JSON tools.

How does Prism compare to jsonlint.com?

Prism provides all the JSON linting features of jsonlint.com plus offline processing, tool chaining, and complete data privacy. No data is ever uploaded to a server.