Free JSON Formatter Online
Paste messy JSON and get it back clean, indented, and readable — entirely in your browser. No data is sent to any server.
How it works
Paste your JSON
Paste raw, minified, or malformed JSON into the input panel.
Click Format
The formatter validates and re-serialises your JSON with 2-space indentation.
Copy or download
Copy the formatted output to your clipboard or download as a .json file.
Stay private
Everything runs in your browser tab. Your JSON never touches a server.
Common use cases
Debugging API responses
Minified JSON from a REST or GraphQL API becomes instantly readable — trace nested objects and arrays in seconds.
Config file cleanup
Make package.json, tsconfig, or any JSON config human-friendly before committing to version control.
Log analysis
Parse dense JSON log lines from your server or cloud provider into structured, indented output.
Teaching & documentation
Produce clean, well-indented examples for docs, README files, or code reviews.
Frequently asked questions
Is this JSON formatter free?
Yes — completely free, forever. No account, no credit card, no limits.
Does my JSON get sent to a server?
No. All formatting runs via JSON.parse() and JSON.stringify() inside your browser tab. Nothing leaves your device.
What indentation style does it use?
The formatter uses 2-space indentation by default, which is the most common convention for JSON files.
Will it fix invalid JSON?
No — JSON.parse() is strict. The formatter will show you exactly where the syntax error is so you can fix it manually.
Can I format very large JSON files?
Yes, limited only by your browser's memory. Files up to several megabytes format instantly.
Does it support JSON5 or comments?
No — only standard JSON (RFC 8259). JSON5 and JSONC (with comments) are not valid JSON and will trigger a parse error.
How is this different from JSON Minifier?
The Formatter adds whitespace and newlines for readability. The Minifier removes them to reduce file size.
Can I use this on mobile?
Yes — the tool is fully responsive and works on iOS and Android browsers.