Developer tool
Format and Validate JSON
Validate JSON syntax and format valid data with readable indentation, all processed locally.
Runs locally in your browser
Your text is not uploaded.
Simple steps
How it works
- 01
Paste JSON into the editor.
- 02
Choose an indentation size and review any error line.
- 03
Copy the formatted JSON or clear the editor.
Good to know
Frequently asked questions
Does formatting change JSON values?
No. Formatting changes whitespace only; the parsed JSON data stays the same.
How are syntax errors shown?
The output explains the parse error, and the editor marks the reported source line when the browser provides a line position.
Which indentation sizes are available?
Choose two spaces, four spaces, or tabs.
Does validation send JSON to a server?
No. Parsing and formatting happen locally in your browser.
Can this repair invalid JSON automatically?
It reports syntax errors but does not guess how you intended to fix the data.