JSON Formatter is a free online tool that turns messy or minified JSON into readable, indented text. It's handy when you're inspecting an API response, editing a config file, or just want to check whether a piece of JSON is valid. Paste your text in, click 'Format' to get clean, indented output, or 'Minify' to strip it down to a single compact line. If you paste invalid JSON, you'll get a clear error message explaining what went wrong. Everything runs in your browser — your data is never sent to a server, so it's safe to paste sensitive API responses or config files.
How to Use It
- Paste your JSON into the text box.
- Click 'Format' to get clean, indented output.
- Click 'Minify' to collapse it to a single line.
- If your JSON is invalid, read the error message and fix it.
- Use the copy button to grab the result.
Use Cases
- Making API responses readable
- Formatting a config file before editing it
- Quickly checking whether a piece of JSON is valid
- Minifying JSON to shrink its size
Frequently Asked Questions
Is my data sent to a server?
No, all formatting happens in your browser; your JSON is never sent anywhere.
What happens if I paste invalid JSON?
You'll see a warning explaining what's wrong and, where possible, where the error is.
Can it handle large JSON files?
Yes, as long as your browser has enough memory to hold the data.
What does minifying do?
It strips unnecessary whitespace and line breaks to shrink the data, useful for API requests or sharing files.