JSON Formatter & Validator
Paste JSON to format, validate, and explore as a tree.
Enter valid JSON to see tree view
About this tool
Format, validate, beautify, and minify JSON online. Collapsible tree view, error detection with line numbers. Free, fast, runs entirely in your browser — no data sent anywhere.
Frequently asked questions
What is a JSON formatter?
A JSON formatter takes minified or messy JSON and adds proper indentation and line breaks to make it human-readable. It also validates the JSON against the specification and highlights any errors.
Why does my JSON fail validation?
Common causes: trailing commas, single quotes instead of double quotes, unquoted keys, or comments. JSON does not support comments.
Is this JSON formatter free?
Yes. Completely free, runs in your browser, no data sent anywhere.