JSON Formatter
Updated on:Format, validate and minify JSON online. Free developer tool.
How it works
1. Paste JSON in the field. 2. Choose Format or Minify. 3. Click Execute. 4. Copy the result.
When to use it
The JSON formatter is essential for developers in many situations:
- API debugging: format API JSON responses to easily inspect received data.
- Web development: validate and format JSON configuration files (package.json, tsconfig.json, appsettings.json).
- Testing: prepare well-formatted JSON payloads for testing REST or GraphQL endpoints.
- Documentation: create readable JSON examples for API technical documentation.
- NoSQL databases: visualize and validate MongoDB, CouchDB or Firestore documents.
Advantages
Instant formatting. Automatic validation with error messages. Supports complex JSON.
Benefits vs alternatives
Advantages of our JSON formatter over alternatives:
- Built-in validation: the tool identifies JSON syntax errors and indicates their exact position.
- No browser extension required: works directly in the page, without installing DevTools plugins.
- Privacy: JSON code is not sent to external servers. All processing happens in the browser.
- Customizable formatting: indentation with spaces or tabs, minification and compression included.
- Free and unlimited: no size limits or usage caps, unlike many online tools.
Common mistakes to avoid
- Trailing comma: JSON does not allow a comma after the last element in an array or object. This is the most common syntax error.
- Comments in JSON: unlike JavaScript, standard JSON format does not support comments. Use JSONC if your tool supports it.
- Single quotes: JSON requires double quotes (") for strings and keys. Single quotes (') are not valid.
- Unquoted keys: every JSON key must be enclosed in double quotes: {"key": "value"}, not {key: "value"}.
- Wrong encoding: special characters, emoji or non-UTF-8 text can cause parsing errors. Make sure the text is UTF-8.
Description
Free Online JSON Formatter
Our JSON formatter allows you to format, validate and view JSON code in a readable way. Ideal for developers working with REST APIs, NoSQL databases and application configurations.
Features
- Customizable indentation formatting
- JSON syntax validation
- Minification to reduce size
- Syntax error highlighting
Uses
API response debugging, configuration formatting, JSON data validation, technical documentation.
FAQ
Yes, after the page loads the formatter runs entirely in your browser. Your JSON data is never sent to any server.
The formatter handles JSON up to a few megabytes without issues. For very large files (>5 MB) we recommend using a desktop tool.
Minifying JSON means removing all unnecessary whitespace, tabs and line breaks, reducing file size. It is useful for optimizing API responses.
Yes, in addition to formatting with indentation, the tool immediately highlights syntax errors such as missing commas or unclosed brackets.
Try this tool now
Format and validate your JSON in one click. Indentation, minification and validation. All free.
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