JSON Formatter
Format, validate and minify JSON online. Paste your JSON and get clean, indented output with clear error messages.
Your JSON is processed entirely in your browser. Nothing is uploaded to a server.
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How to use this tool
- 1Paste or type your JSON into the input box.
- 2Your JSON is validated automatically as you type, showing the exact line and column of any error.
- 3Click Format to pretty-print it with indentation, or Minify to compact it onto one line.
- 4Copy the result or download it as a .json file.
Features
- Automatic validation as you type, with line and column for errors.
- Format: pretty-print JSON with 2-space indentation.
- Minify: compact JSON onto a single line.
- Copy result to clipboard, or download as a .json file.
- Handles large JSON without freezing the page (validation is debounced).
- No account or sign-up required.
Privacy
Your JSON is processed entirely in your browser. It is never sent to a server, logged or stored.
Frequently asked questions
Is this JSON formatter free?
Yes. You can format, validate and minify unlimited JSON for free, with no sign-up required.
What happens if my JSON is invalid?
You'll see the parser's error message along with the exact line and column where the problem starts, so you can find and fix it quickly.
What's the difference between Format and Minify?
Format adds indentation and line breaks to make JSON easier to read. Minify removes all unnecessary whitespace to make the file as small as possible.
Is my JSON data sent to a server?
No. Formatting, validating and minifying all happen locally in your browser using the JSON built into JavaScript.
Is there a size limit?
There's no hard limit, but very large JSON files (tens of megabytes) may be slow to process since everything runs in your browser tab rather than on a server.
Guides
- What Is JSON and How Do You Format It Correctly?
A plain-English explanation of JSON, why formatting and validation matter, and how to instantly clean up messy or minified JSON for free.
- How to Compare Configuration Files Without Missing Meaningful Changes
Review configuration changes with line, word, and character diffs, avoid misleading whitespace filters, and separate textual differences from semantic checks.
- Why Large JSON IDs Change: JavaScript Number Precision Explained
Understand why a JSON formatter can change large numeric IDs, how to preserve identifiers as strings, and how to check a safe sample before formatting.
- How to Compare Two Texts and Find the Differences
Which clause changed in the contract? What did the editor rewrite? Here's how to compare two versions of any text and see every change highlighted, free.