JSON formatter & validator
JSON Formatter — beautify, minify & validate
Paste messy or minified JSON and format it instantly with proper indentation, or minify it back down to a single line. Invalid JSON is flagged inline with the exact line and column so you can fix it fast.
Runs in your browser. No uploads, no accounts, free.
How it works
- Step 1
Paste your JSON
Drop in raw, minified, or malformed JSON. The source editor auto-formats valid input as soon as you paste.
- Step 2
Format or minify
Beautify with clean 2-space indentation, or minify to a compact single line — one click each, in the Source pane.
- Step 3
Catch errors instantly
Syntax errors are underlined in the editor with the precise line and column, so you know exactly what to fix.
Real editor, not a textarea
A CodeMirror-based source editor with syntax highlighting, line numbers, code folding, and find/replace.
Format and minify
Pretty-print for readability or minify for transport, then copy the result to the clipboard in one click.
Inline validation
Invalid JSON is highlighted as you type, with the error message and exact position surfaced right away.
Private and free
Formatting happens locally in your browser — no uploads, no accounts, no limits beyond a generous 10 MB file size.
Frequently asked questions
- How do I format (beautify) JSON?
- Paste your JSON into the Source pane — valid JSON is auto-formatted on paste — or click Format to pretty-print with 2-space indentation.
- Can I minify JSON too?
- Yes. The Minify action collapses formatted JSON back to a single compact line, ready to copy.
- Does it validate JSON?
- Yes. Invalid JSON is underlined inline with the error message and the exact line and column, so you can fix it quickly.
- Is my data sent to a server?
- No. Formatting and validation run entirely in your browser. Your JSON never leaves your machine.