JSON Beautifier
Format & validate JSON
{
"user": {
"id": 42,
"name": "Ada",
"active": true,
"tags": [
"eng",
"lead"
],
"meta": {
"created": "2024-01-01",
"score": 9.7
}
}
}What is JSON Beautifier?
Format, validate, and minify JSON in one screen. Live syntax-error reporting tells you the exact line and column where parsing broke; a toggle lets you sort object keys for deterministic output useful in diffs and snapshots. Handles deeply nested structures, accurately round-trips numbers within JavaScript's safe-integer range, and shows byte counts before and after.
How do I use JSON Beautifier?
- Paste JSON into the input panel.
- Choose Pretty or Minify mode, and set indent size.
- If valid, the output panel shows the formatted JSON with syntax highlighting.
- Copy or download the result.
JSON Beautifier by the numbers
- Parser
- Native JSON.parse
- Indent options
- 2, 4, or tab
- Max comfortable size
- ~50 MB
- Error reporting
- Line + column of first error
- Key-sort
- Optional, alphabetic, recursive
Common use cases for JSON Beautifier
- Pretty-printing an API response captured from a browser Network tab.
- Diffing two JSON configs after alphabetising keys.
- Preparing a README example from a minified payload.
- Spotting a trailing comma or missing quote in a broken manifest.
- Normalising fixtures before committing them to a test suite.
Common pitfalls and how to avoid them
- Parser complains about trailing commas — Strict JSON bans trailing commas. Remove them or paste into a JSON5-capable tool first.
- Keys come out in an unexpected order — Toggle off "Sort keys" if you want to preserve insertion order. Toggle it on for deterministic diffs.
- Large file freezes the tab — JSON.parse blocks the main thread on huge inputs (tens of MB). Split the file or use a streaming parser outside the browser.
When should I use JSON Beautifier?
Beautifier is the right tool for formatting and validation. For aggressive minification only (one-line output), use JSON Minifier. To generate TypeScript interfaces from a JSON sample, use JSON to TS.
My JSON is invalid — can the tool auto-fix it?
No. We show the line and column of the first parse error so you can fix it yourself. Common issues: trailing commas, unquoted keys, single quotes instead of double. Strict JSON requires double-quoted keys and no trailing commas.
What does "Sort keys" do?
Recursively sorts object keys alphabetically. Useful for comparing two JSON documents or producing deterministic output for diffing.
How big a JSON file can I paste?
Tens of megabytes work without issue. Past that, JSON.parse can briefly block the main thread — consider splitting the file.
Is my file uploaded anywhere?
No. Everything runs in your browser. Your files never leave your device, and there is no server component for this tool.