Free online tool
JSON Formatter
Format, validate, and minify JSON data — instantly in your browser.
Input
Privacy: All processing happens in your browser. No data is stored or sent to any server.
Frequently asked questions
Is my data sent to any server?
No. All processing happens entirely in your browser using JavaScript's built-in JSON.parse() and JSON.stringify(). Nothing is transmitted over the network.
What size JSON can this handle?
It works well with files up to several megabytes. Very large files (10 MB+) may cause the browser to slow down temporarily.
What does the Validate button do?
It checks whether your input is syntactically valid JSON and reports the first error with its position if not.
Can I format JSONL or JSON5?
This tool parses standard JSON (RFC 8259). JSONL files should be split line by line, and JSON5 must be converted to standard JSON first.