JSON Formatter — Free Online JSON Beautifier, Validator & Minifier
Format, validate, and minify JSON online. Free, no signup — your data never leaves your browser.
Input
Invalid JSON — line , column
Paste JSON to see tree view.
How to use
- 1 Paste your JSON into the input panel on the left.
- 2 Pick indent size (2, 4, or tab) and toggle Sort keys if needed.
- 3 View the formatted, minified, or tree output on the right. Copy or download with one click.
Why use this tool
- Runs entirely in your browser — your JSON never leaves your device.
- Real-time syntax validation with line and column error reporting.
- Switch between pretty, minified, and collapsible tree views.
- Resizable split-pane, fullscreen mode, and live stats for large payloads.
- Free, no signup, no ads, no rate limits.
Frequently asked questions
Is this JSON formatter really free?
Yes — completely free. No signup, no ads, no rate limits. The formatter runs in your browser so your data never reaches our servers.
How large a JSON file can it handle?
Up to ~10 MB efficiently. For very large payloads, paste in chunks or use a streaming parser.
Does it validate JSON syntax?
Yes — real-time validation. When parsing fails, the error includes a line and column so you can jump straight to the problem.
Can I sort object keys alphabetically?
Yes. Toggle "Sort keys" in the settings bar. The sort is recursive — nested objects are sorted too.
What about minification?
Switch the output to Minified to strip all whitespace. Useful for reducing payload size before transport.
Can I resize the input and output panels?
Yes — drag the divider between the panels on desktop. Double-click the divider to reset to a 50/50 split. Each panel also has a fullscreen toggle.
What is JSON Formatter?
A JSON Formatter is a tool that converts compact or minified JSON data into a structured, indented form for readability, and reverses the process for transmission. It validates syntax against RFC 8259 / ECMA-404, detects errors with line and column positions, and renders output as pretty-printed text, minified text, or a collapsible tree.
How JSON Formatter compares to alternatives
| Feature | Zerethon Tools | Typical online tools | Desktop apps |
|---|---|---|---|
| Signup required | No | Sometimes | Sometimes |
| Data leaves device | No | Yes (server-side) | No |
| Free | Yes | Yes (with ads) | Sometimes paid |
| Works offline | Yes (after load) | No | Yes |
| Max input size | ~10 MB | 1–5 MB | Unlimited |
| Tree view | Yes | Sometimes | Yes |
| Error line + column | Yes | Sometimes | Yes |
JSON Formatter is a free developer utility by Zerethon Tools. Format, validate, and minify JSON online. Free, no signup — your data never leaves your browser. Runs entirely in the browser — no signup, no upload.
- Category
- Developer
- Pricing
- Free
- Privacy
- Browser-based
- Signup
- Not required
Privacy
Your data never leaves your browser unless explicitly stated. JSON Formatter runs entirely client-side — no server upload, no logging, no tracking of your input.
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