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JSON Formatter

Prettify or minify JSON with syntax error detection. Choose your indent style. Everything runs in your browser - no server, no tracking.

Developer Tools Runs locally No data sent
JSON.parse prettify minify validate client-side only
Indent:
Recent
No history yet
Input JSON
0 chars
→
Formatted JSON
0 chars ✓ Valid JSON
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JSON is validated using JSON.parse(). Syntax errors include the line and column number where parsing failed. Prettify adds indentation and line breaks for readability. Minify removes all whitespace to minimize file size. Keyboard shortcut: Ctrl/Cmd + Enter to format.

What is JSON Formatter?

Format, minify, and validate JSON online. You can also convert JSON to CSV or SQL INSERT statements, all locally in your browser.

Why Use This JSON Formatter?

Most online JSON formatters send your data to a server to process it. This one does not. Everything -formatting, validation, conversion -runs entirely in your browser using JavaScript. That means your API keys, config files, and private payloads never leave your machine. It also means the tool works offline once the page has loaded.

  • No upload: Your JSON stays in your browser tab, not on a server.
  • Error highlighting: Syntax errors are flagged with line numbers so you can fix them fast.
  • Multi-format output: Convert to CSV or SQL INSERT in one click -useful for data migration and reporting.
  • No sign-up: Paste, format, done. No account, no email, no waiting.

How to Use JSON Formatter

  1. Paste your JSON into the input panel on the left.
  2. Click Prettify to format it or Minify to compress it for transport.
  3. Fix any syntax errors shown in the validation message area if the JSON is invalid.
  4. Copy the cleaned output or switch to CSV or SQL conversion if you need another format.

Quick Guides

JSON Formatting Guide covers prettify vs minify, escaping rules, and the most common validation mistakes.

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Understand JSON Formatting ▾
Example
Input {"name":"Alice","age":30}
Output { "name": "Alice", "age": 30 }
Common Use Cases
  • Prettify minified API responses while debugging
  • Validate JSON before saving config or request bodies
  • Convert JSON into CSV or SQL-ready structures
  • Clean sample payloads for documentation and demos
Frequently Asked Questions
What JSON standards does this support?

Standard JSON (RFC 8259). JSONC (with comments) is not supported. Remove comments before pasting.

How do I convert JSON to CSV?

Paste a JSON array of objects into the input, then click the "JSON to CSV" tab. Each key becomes a column.

Is there a size limit?

No hard limit, but very large files (>10 MB) may slow down your browser. For large data, consider a dedicated CLI tool.

Is this JSON Formatter free?

Yes. The tool is completely free with no sign-up required. Everything runs in your browser -no data is ever sent to a server.

Does this tool upload my JSON to a server?

No. Your JSON is never uploaded anywhere. All formatting, validation, and conversion happens locally in your browser using JavaScript.