JSON Formatter

Beautify, minify and validate JSON instantly — nothing leaves your browser.

How it works

Paste your JSON and the tool parses it with your browser's native JSON engine — the same parser used by JavaScript itself, so its validation is exact. "Beautify" re-serialises the data with clean indentation so nested structures are easy to read, while "Minify" strips all optional whitespace to produce the smallest valid output. If the text isn't valid JSON, you get a clear error pointing to the line and column where parsing failed. Nothing is sent anywhere; all of it happens locally in your browser.

Formatting and validating

Well-formatted JSON is far easier to scan, debug and diff, which is why beautifying is the first thing many people do with an API response or a config file. Choose two spaces, four spaces or tabs to match your project's style. Minifying does the opposite: it removes indentation and line breaks to shrink a payload before sending it over a network or embedding it somewhere size matters. Because both operations run through a real parser first, a successful format also confirms the JSON is valid.

Reading error messages

When parsing fails, the status line reports the line and column of the problem so you can jump straight to it. Common causes are trailing commas, single quotes instead of double quotes, unquoted keys, or a missing bracket or brace. Fix the flagged spot and format again — the message updates until the JSON parses cleanly.

Frequently asked questions

Is my JSON sent to a server?

No. Parsing, formatting and validation all happen in your browser, and your data never leaves your device.

Does it support very large JSON?

Yes, within your browser's memory. Extremely large files may be slower since everything is processed on your device.

Why does it reject trailing commas?

Standard JSON does not allow trailing commas. Remove the extra comma before the closing bracket or brace and format again.