How to Format JSON Online (Pretty Print and Validate)

What this formatter does

JSON Formatter pretty-prints JSON with 2 or 4 space indentation, updates as you type, and flags invalid input with the line and column where parsing stopped. A green badge confirms valid JSON; a red badge with an error message points to the first problem.

Everything runs locally in your browser — your JSON never leaves your device, and the tool keeps working offline after the page has loaded once.

1. Paste your JSON

Copy raw or minified JSON from your clipboard, a terminal, or an API response and paste it into the input area. Formatting starts immediately, so there is no button to click.

2. Choose an indent size

Use the 2 spaces or 4 spaces buttons to switch indentation. The formatted output and character count update immediately, and the minified version stays available below it.

3. Check validity

Valid JSON is confirmed with a green badge. For invalid input the badge turns red and you get an error message with the line and column where parsing stopped — useful for spotting a stray comma, a missing quote, or a truncated paste.

4. Copy the result

Copy the readable formatted output with Copy formatted, or grab the compact single-line version with Copy minified. Both clipboard buttons work in any recent browser without extra permissions.