JSON Formatter & Validator
API response squashed onto one line? Paste it to get readable JSON instantly — and the exact spot of any error.
This tool runs entirely in your browser. Nothing you add is uploaded to any server.
Last checked: · Made by Fingertip Workshop
How to use
- 1
Paste JSON on the left.
- 2
The formatted result appears on the right, with a validity check and error location below.
- 3
Choose indentation or Minify, then copy or save as a file.
Common JSON mistakes
| Wrong | Right |
|---|---|
{'name': 'kim'} — single quotes | {"name": "kim"} |
{"a": 1,} — trailing comma | {"a": 1} |
{name: "kim"} — unquoted key | {"name": "kim"} |
// comment | JSON has no comments |
Indent or minify?
Indentation is for humans; minified JSON is smaller for storage and transfer. Sorting keys makes comparing two JSON files far less noisy.
JSON with API keys or personal data stays safe — everything runs in your browser.
FAQ
Can it handle big files?
Several MB is fine; tens of MB may slow your browser.
A long number changed.
JavaScript can't exactly represent integers above about 9 quadrillion. Store such values as strings.
JSON to Excel?
Not yet — let us know if you'd like it!