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JSON Formatter

LOCAL · Browser-Only

Format, validate, and beautify JSON data with syntax highlighting

Go ad-free, save JSON workspaces, and get the REST API with ToolBox Pro →

Indent:

Sort keysAuto-formatLine numbers

Input JSON

Output

Paste JSON in the input panel and click Format to see the result here

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What is JSON Formatter?

JSON formatter online to format, beautify, and validate JSON data instantly with syntax highlighting.

Paste raw or minified JSON and get properly indented output with a single click. The tool validates your JSON structure in real time, highlights syntax errors with clear line-by-line messages, and can minify formatted JSON for production use. Use it as a JSON viewer to pretty print an API response, fix indentation on a messy config file, or check whether a string is valid JSON before you ship it. Choose between 2-space, 4-space, or tab indentation depending on your project's style. All processing runs entirely in your browser using JavaScript - your data never leaves your device and is never logged or stored anywhere. Unlike some online formatters that send your data to a server for processing, ToolBox keeps everything client-side. No signup, no account, no tracking. Just paste, format, and copy.

How to Use JSON Formatter

1Paste your raw, minified, or malformed JSON data into the input field on the left side of the editor
2Select your preferred indentation level from the dropdown - 2 spaces, 4 spaces, or tab characters
3Click 'Format' to beautify your JSON with proper indentation, or click 'Minify' to compress it into a single line
4Review the formatted output on the right side, then click 'Copy' to copy the result to your clipboard

Frequently Asked Questions

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write, and easy for machines to parse and generate. It is the standard format for web APIs, configuration files, and data storage across virtually every programming language.

How do I format JSON online?

Paste your raw or minified JSON into the input field, select your preferred indentation (2 spaces, 4 spaces, or tab), and click the Format button. The formatted JSON will appear instantly in the output panel with proper syntax highlighting.

Does this tool validate JSON?

Yes. When you click Format or Minify, the tool automatically validates your JSON. If the JSON is invalid, a clear error message will show you exactly what went wrong and where the syntax error is located, including the line number and character position.

Is my JSON data safe?

Yes. All processing happens locally in your browser using JavaScript. Your JSON data is never sent to any server, never logged, and never stored. This makes the tool completely safe for API keys, configuration secrets, and proprietary data structures.

Can I minify JSON with this tool?

Yes. Click the 'Minify' button to compress your formatted JSON into a single line with no whitespace. This is useful for reducing payload size in production APIs, configuration files, and network requests.

What is the difference between JSON formatting and validation?

Formatting takes valid JSON and adds indentation and line breaks to make it readable. Validation checks whether the JSON syntax is correct - matching braces, proper quoting, valid data types. This tool does both in one step, so you get formatted output if valid, or a clear error message if not.

Is this a free alternative to JSONLint?

Yes. This tool provides the same formatting and validation as JSONLint, plus additional features like customizable indentation, minification, and syntax highlighting. Unlike JSONLint, all processing happens client-side in your browser with no data sent to external servers.

Does the formatter handle large JSON files?

Yes. Since the tool runs in your browser, it can handle large JSON payloads limited only by your device's memory. Most modern devices can format JSON files several megabytes in size without issues.

How do I pretty print a minified API response?

Copy the raw response from your network tab or terminal, paste it into the input, pick 2-space or 4-space indentation, and click Format. The tool expands the single line into readable, indented JSON you can scan key by key.

Can I use this as a JSON viewer without changing the data?

Yes. Formatting only adds indentation and line breaks, it does not alter keys, values, or ordering. Paste your JSON to read it cleanly, then copy it back out unchanged or in your preferred indentation style.

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Keep reading: JSON Syntax Cheat Sheet and http status codes reference. Doing this in code instead? See the JSON and data endpoints.