Free Online JSON Formatter & Validator
Free Online JSON Formatter & Validator
Paste messy API responses or config files and validate JSON instantly. Beautify with readable indentation, minify for production payloads, or follow line-by-line error hints—everything runs locally in your browser with no sign-up. Read the JSON tutorial · Read the JSON blog
Why developers use this JSON tool
Format & beautify JSON
Turn minified or messy JSON into readable 2-space indented output with syntax highlighting—ideal for debugging APIs and reading configs.
Validate with precise errors
Invalid JSON shows the error message, line and column, a snippet of the broken line, and actionable fix suggestions (trailing commas, quotes, brackets).
Minify JSON for production
Remove whitespace and newlines to produce compact, standard JSON suitable for logs, HTTP bodies, and storage.
Private by design
Processing stays in your browser. Nothing is uploaded to a server—safe for tokens, PII, and internal API payloads.
JSON formatter FAQ
- Is this JSON formatter free?
- Yes. Formatting, validation, minify, copy, download, and undo/redo are free with no account required.
- Is my JSON uploaded to your servers?
- No. Validation and formatting run entirely in your browser using JavaScript. Your data never leaves your device.
- What is the difference between format and minify?
- Format (beautify) adds indentation and line breaks for readability. Minify removes extra whitespace to make the smallest valid JSON string.
- How do I fix invalid JSON?
- After paste, the tool highlights the error line. Check double-quoted keys and strings, matching brackets, commas between properties, and no trailing comma before } or ].
- Does it support large JSON files?
- You can upload text files up to 4 MB. Very large files may be slower depending on your device; split huge payloads if needed.
- Can I download or copy the result?
- Yes. Use Copy for the clipboard or Download to save as a .json file with a custom filename.