JSON Formatter
Format, validate, and minify JSON with instant error feedback.
Paste JSON above to get started.
Key features
Paste in JSON and it’s validated and pretty-printed instantly, with a clear error message (including the line and column) if something’s wrong. Switch to Minify to collapse it down to a single line instead.
Everything is parsed and formatted locally in your browser — nothing you paste is ever sent to a server.
How to use
Paste your JSON
Paste in JSON from an API response, a config file, or anywhere else.
See it validated instantly
Valid JSON is pretty-printed on the right; invalid JSON shows exactly what's wrong and where.
Copy the result
Switch between Pretty and Minify, then copy the formatted output.
Frequently asked questions
Is my JSON uploaded anywhere?
No. Parsing and formatting both happen locally in your browser using the standard JSON.parse/JSON.stringify — nothing is sent to a server.
What does the error message mean?
It's the browser's own JSON parser telling you exactly where parsing failed — usually a missing comma, an extra trailing comma, or unquoted keys. The line and column point to the character right after the last valid part of the JSON.
What's the difference between Pretty and Minify?
Pretty adds 2-space indentation and line breaks so nested JSON is easy to read. Minify strips all unnecessary whitespace down to a single line, which is useful when you need the smallest possible payload.