Does pretty printing alter the data?

No. Only whitespace between tokens is added; values and key order are unchanged.

Can it fix invalid JSON?

It reports the error location but does not silently repair it, so you can fix the source.

Does it handle very large files?

It formats up to the record limit for your account, all in the browser.

JSON pretty print

Pretty-printing makes a one-line API response readable. Paste it, choose 2 or 4 spaces or a Tab, and the output is indented with each key on its own line.

This formatter is built for data you cannot paste into a random site: it works in the browser, keeps large numbers intact, and points at the exact line and column when the JSON is invalid.

Formatted JSON

Paste JSON and press Format

Formatting happens in this browser. Numbers are kept exactly as written.

How to use this tool

1Open the Format JSON tool.
2Paste a compact JSON string.
3Choose an indent width.
4Copy the pretty-printed result.

Frequently asked questions

Does pretty printing alter the data?: No. Only whitespace between tokens is added; values and key order are unchanged.
Can it fix invalid JSON?: It reports the error location but does not silently repair it, so you can fix the source.
Does it handle very large files?: It formats up to the record limit for your account, all in the browser.
Can I get the output as a file?: Yes, use Download .json.

Private by design

This tool runs entirely in your browser. Files, tables, and results are never uploaded to a server — you can even disconnect your network and keep working. See the Privacy Policy.