JSON Formatter
Format, validate, and beautify JSON data
The JSON Formatter parses, validates, minifies, and pretty-prints JSON so you can move between raw payloads and readable structure quickly. It also includes a tree view for nested objects and arrays, with all parsing done locally in your browser.
All processing runs locally in your browser. Your files and text are not sent to Tool-web's server.
How to Use
- Paste JSON into the input area
- Choose Format, Minify, Validate, or Tree mode
- Run the selected action or let the live parser update the result
- Copy or download the output when you're done
Features
- Format, minify, validate, and tree-view modes
- Live parser feedback plus manual run button
- Reports JSON depth, key count, lines, and bytes
- Tree explorer for nested objects and arrays
- Copy, download, share, and reset actions
Tips for getting JSON Formatter right
- Validate before you format — the tool tells you when and where the JSON breaks
- Use a smaller indent (2 spaces) for deeply nested data to keep lines from wrapping
- Copy the original minified JSON first if you ever need the compact version back
- Switch to Tree mode when a formatted payload is still too long to scan comfortably
Worked example: inspect a nested API response
Paste a minified response from an API log, switch to Tree mode, and expand only the branches you care about. You can validate the payload, inspect nested arrays without endless horizontal scrolling, then switch back to Format mode to copy a readable version into a ticket or document.
What each mode is for
| Mode | Best use |
|---|---|
| Format | Readable indentation for debugging or review |
| Minify | Compact output for transport or fixtures |
| Validate | Quick pass/fail check with a parser error message |
| Tree | Explore large nested objects one branch at a time |
Real-World Use Cases
- Formatting minified JSON API responses for debugging
- Pretty-printing JSON configuration files
- Validating JSON structure before sending to a server
- Inspecting nested JSON data for data analysis
- Preparing JSON for documentation and presentations
Best Practices
- Always validate JSON before and after formatting
- Use appropriate indentation levels (2 or 4 spaces) for readability
- Check for encoding issues when pasting from web pages or emails
- Keep the original minified JSON as backup
- Switch to Tree mode when the formatted payload is still too long to scan comfortably
Common Mistakes to Avoid
- Pasting JSON with trailing commas which is invalid
- Not validating the JSON structure before formatting
- Assuming formatting will fix logical errors in JSON data
- Not checking encoding when pasting from different sources
- Forgetting that JSON keys are case-sensitive
Troubleshooting
- If JSON won't format, check for syntax errors like trailing commas
- For encoding issues, try pasting raw text instead of formatted content
- If the tool seems stuck, clear the input and paste fresh data
- Try a different browser if formatting consistently fails
- Verify you're pasting valid JSON rather than a JavaScript object literal or YAML
Frequently Asked Questions
Does it detect JSON errors?
Can I minify JSON?
Is there a size limit?
Privacy & Security
All JSON formatting and validation happens in your browser. Your data — including API keys, tokens, or configuration values — is never sent to external servers.
Tips & Best Practices
- Validate before you format — the tool tells you when and where the JSON breaks
- Use a smaller indent (2 spaces) for deeply nested data to keep lines from wrapping
- Copy the original minified JSON first if you ever need the compact version back
- Switch to Tree mode when a formatted payload is still too long to scan comfortably
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