Paste your JSON below to format, validate, or minify. Everything happens locally — your data never leaves your browser.
About this JSON Formatter
JSON (JavaScript Object Notation) is the most common data interchange format on the web. This tool helps developers format, validate, and minify JSON directly in the browser — no data is uploaded to any server.
Features
- Format / Pretty-print — convert minified JSON into a readable indented form.
- Minify — strip whitespace to produce the smallest possible JSON.
- Validate — check whether your JSON is syntactically correct, with the line and column of any error.
- Configurable indent — 2 spaces, 4 spaces, or tab.
- Privacy — runs entirely client-side. Your JSON is never transmitted.
How to use
- Paste your JSON into the Input field on the left.
- Click Format to pretty-print, Minify to compress, or Validate to check syntax only.
- Use Copy Output to copy the result to your clipboard.
Common JSON errors
Unexpected token — usually a stray comma or missing quote. JSON does not allow trailing commas.Unexpected end of JSON input — an unclosed bracket or brace.- Single quotes — JSON requires double quotes around strings and keys.
- Comments — standard JSON does not support
// or /* */ comments.
Frequently Asked Questions
Is this JSON formatter free to use?
Yes. The tool is completely free, with no sign-up, no rate limits, and no watermarks.
Is my JSON data sent to a server?
No. All formatting, validation, and minification happens entirely in your browser using JavaScript. Your JSON never leaves your device.
What is the difference between Format and Validate?
Format pretty-prints valid JSON with indentation. Validate only checks whether the JSON is syntactically correct without producing output. Use Validate when you only need a yes/no answer.
Why does my JSON show "Unexpected token"?
This usually means a syntax error: a stray comma, single quotes instead of double quotes, missing brackets, or comments (which standard JSON does not support). The error message includes the position to help you locate it.
Can it handle large JSON files?
Yes. Because everything runs locally, the tool is limited only by your device's memory. Files up to several megabytes typically work without issue. For files larger than 50 MB, browser performance may slow down.
Why would I want to minify JSON?
Minified JSON removes all unnecessary whitespace, reducing file size by 20–50%. This is useful when sending JSON over a network, embedding it in a URL, or storing it where bytes matter.