Private by default
Your JSON never leaves this page. There is no account, upload, or server-side processing.
Developer tool
JSON formatter and validator.
Paste JSON, check that it is valid, and turn it into readable code. Everything happens in your browser.
Ready to format JSON.
Clean up JSON without sending it anywhere.
JSON is easy for software to read but awkward to scan when it is packed onto one line. This tool parses your input in the browser, reports invalid syntax, and applies the indentation you choose.
Useful error feedback
If the input cannot be parsed, you will get a pointer to the likely character position.
Ready to reuse
Copy the result or download a clean .json file when it is valid.
How to use it
- Paste JSON from an API response, configuration file, or application log.
- Choose two spaces, four spaces, or compact output.
- Select “Format and validate JSON”, then copy or download the result.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
Does this JSON formatter upload my data?
No. Formatting and validation happen in your browser. The JSON you paste is not uploaded to CodeASystem.
Why does my JSON fail validation?
JSON requires double quotes around keys and text values, commas between items, and matching brackets and braces. The tool highlights when it cannot parse the input and, when possible, points to the character area to check.
Can I download formatted JSON?
Yes. Once your JSON is valid, use the Download button to save it as formatted.json.