JSON Formatter & Validator

How to use JSON Formatter

1. Paste raw JSON into the input area — the tool parses it in real time.
2. If the JSON is valid, a beautified (2-space-indented) version appears in the output.
3. If invalid, the error shows the exact line and column where parsing failed — usually the character just before the missing bracket, quote, or comma.
4. Click Minify to strip all whitespace for embedding in URL params, JS strings, or config files.
5. Click Copy to grab the output for pasting elsewhere.

Common use cases

• API response debugging. Paste a minified API response to inspect its structure. The tree view makes deeply nested objects readable at a glance.
• Config file cleanup. package.json, tsconfig.json, and .eslintrc all use JSON. Beautify before committing so diffs stay clean.
• Embedding JSON in code. Minify JSON when embedding it in a JS/TS string, a URL query parameter, or a database column — every byte counts.
• Learning JSON. Error messages point exactly to the offending character, making the tool a good teaching aid for JSON syntax rules.

Tips

• Trailing commas are the most common cause of invalid JSON. Strict JSON does not allow them, even though JavaScript objects do.
• Use double quotes (") for keys and string values — single quotes cause syntax errors.
• JSON does not support comments. If you need commented config, consider JSONC or YAML.
• For huge JSON (>10 MB), performance depends on your browser — the tool runs in a single thread and may briefly hang.

Troubleshooting

'Unexpected token' error at column 1.

Your input may include a leading BOM or non-printable characters from a PDF/Word copy-paste. Retype the first character or use the case-converter to strip whitespace.

Numbers lose precision after formatting.

JavaScript numbers are 64-bit floats, so integers larger than 2^53 lose precision. For financial or ID fields, wrap large numbers in strings on the source side.