Dev Tool

JSON Formatter & Beautifier

Format, validate, and minify JSON instantly. Runs entirely in your browser — your data never leaves your device.

Input JSON 0 chars

Output 0 chars

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Instant formatting

Paste any JSON and format it instantly with proper indentation and syntax.

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Real-time validation

Detects syntax errors immediately and shows which line is broken.

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100% private

All processing happens in your browser. Your JSON data never touches any server.

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Minification

Remove all whitespace to reduce JSON size for production use.

Frequently Asked Questions

Can I validate JSON with this tool?

Yes — the formatter highlights syntax errors and shows where your JSON is invalid before formatting.

What is the difference between pretty print and minify?

Pretty print adds indentation for readability. Minify removes all whitespace to reduce file size, useful for production APIs.

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data interchange format. It is human-readable text used to transmit data between servers and web applications. JSON uses key-value pairs and supports strings, numbers, booleans, arrays and nested objects.

Why is my JSON invalid?

Common causes: missing or extra commas, unquoted keys, single quotes instead of double quotes, trailing commas after the last item, or unescaped special characters in strings. The validator shows the exact line of the error.

What is JSON minification?

Minification removes all unnecessary whitespace, newlines and indentation from JSON. This reduces file size which improves API response times and reduces bandwidth usage in production environments.

What a JSON formatter does

JSON is the format most APIs, configuration files and web apps use to exchange data. Machines often send it minified, on one long line with no spaces, which is efficient to transfer and very hard to read. A formatter adds indentation and line breaks so you can see the structure, and the validator tells you where the syntax breaks. Everything here runs in your browser, so the data you paste is never uploaded.

The errors it catches most often

Trailing commas. {"a": 1,} is valid JavaScript but invalid JSON.
Single quotes. JSON strings and keys must use double quotes.
Unquoted keys. {name: "x"} works in a JavaScript object, not in JSON.
Comments. Standard JSON has no comments, so remove // and /* */ lines before parsing.
Special values. NaN, Infinity and undefined are not allowed. Use null or a string instead.

When to format, minify or sort keys

Format when reading API responses, debugging, or reviewing a configuration change.
Minify before putting JSON into a request body or an HTML attribute, where every byte counts.
Sort keys before comparing two documents. With keys in the same order, the diff checker shows only the real changes.

Keep sensitive data on your device

API responses often contain access tokens, email addresses or customer records. Avoid pasting them into tools that send data to a server; a browser-only formatter like this one keeps them on your computer. If you need the data in a spreadsheet, the JSON to CSV converter turns arrays of objects into rows.