JSON Formatter Online
Paste or upload JSON, then format it with readable indentation, validate it with exact error locations, or minify it — entirely in your browser.
Paste your JSON
Valid JSON ✓
Result
Never uploaded
Formatting happens entirely in your browser — your JSON never touches our servers.
Instant
No waiting, no upload progress bar — results appear the moment you click.
Free, no limit
No account, and no limit on how many times you can use it.
What is a JSON Formatter?
A JSON formatter takes minified or messy JSON and reformats it with consistent indentation, making it readable — useful when debugging an API response, reviewing a config file, or checking data that arrived as one long unreadable line. This tool also validates and minifies, so the same page covers all three related tasks.
How to Format JSON Online
- Paste or upload your JSON. Paste directly into the editor, or click "Upload a file" to load a .json file's contents.
- Choose a mode. Format for readable indentation, Validate to check correctness, or Minify to strip whitespace.
- Click the action button. The result appears below — including the exact line and column if your JSON is invalid.
- Copy or download. Copy the result to your clipboard, or download it as a .json file.
Why Use CurePDF's JSON Formatter
Most online JSON formatters send your data to a server to process it. This one doesn't — formatting, validation, and minification all run using your browser's own built-in JSON parser, so nothing you paste or upload ever leaves your device. That also makes it fast: there's no upload wait, no file-size limit tied to a server request, and no account needed.
Frequently Asked Questions
What is a JSON formatter?
A tool that takes minified or messy JSON and reformats it with consistent indentation, making it readable — useful when debugging an API response or reviewing a config file that arrived as one long unreadable line.
Can I validate JSON online?
Yes. Switch to Validate mode and paste or upload your JSON — invalid JSON shows the exact line and column of the problem, not just a generic error.
Can I minify JSON?
Yes. Switch to Minify mode to strip all whitespace and produce the smallest possible version of your JSON, useful for reducing payload size.
Is my JSON data uploaded anywhere?
No. This tool runs entirely in your browser using your browser's own built-in JSON parser — your data is never sent to CurePDF's servers.
Is the JSON formatter free?
Yes, with no account required and no limit on how many times you can use it.
Does it work on mobile?
Yes, it works the same in a mobile browser as on desktop.
Can I upload a .json file instead of pasting?
Yes — click "upload a file" and choose any .json file; its contents load straight into the editor, the same as pasting.
Can I copy or download the result?
Yes — use the Copy button to copy the formatted, validated, or minified result to your clipboard, or Download to save it as a .json file.