Free JSON Formatter - Format, Validate & Minify JSON Data

How to format JSON

1. Paste your JSON into the editor.
2. Click Format (2 Spaces) or Format (4 Spaces) to pretty-print it with consistent indentation.
3. If the JSON is invalid, the error message shows what went wrong so you can fix it.
4. Click Minify to strip all whitespace for production payloads, then Copy the result.

Validate JSON and find syntax errors

The formatter parses your input with the browser’s native JSON parser, the same one your JavaScript code uses, so if it validates here it will parse in production. The most common errors are trailing commas after the last item, single quotes instead of double quotes around keys and strings, unquoted keys, and comments - none of which are allowed in strict JSON.

A JSON formatter that works offline

API responses and config files often contain access tokens, customer data or internal URLs. Pasting them into an online formatter that sends data to a server is a real leak risk. This tool never transmits what you paste; once the page has loaded you can go offline and it keeps working.

2 spaces, 4 spaces or minified?

Two-space indentation is the convention in most JavaScript projects and keeps deeply nested data readable. Four spaces is common in Python and Java codebases. Minified JSON removes every unnecessary character, which reduces payload size for APIs and storage.

Frequently asked questions

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