The JSON Formatter & Validator takes raw or minified JSON and reformats it with proper
indentation, making it immediately human-readable. It simultaneously validates the JSON
structure and highlights any syntax errors with the position where the problem occurs.
1. Paste your JSON into the input box, upload a .json file, or click Sample to try an example.
2. Choose your indent preference (2 spaces, 4 spaces, or tab).
3. Click Format & Validate to pretty-print with indentation.
4. Use Compact to minify to a single line for production use.
5. Use Sort Keys to reorder all object keys alphabetically.
6. Click Copy to copy the output to your clipboard.
Debugging API Responses
Paste minified API responses to read them easily during development without needing a full IDE.
Validating Config Files
Check package.json, tsconfig.json, and other JSON config files for syntax errors before deploying.
Preparing API Payloads
Compact formatted JSON into a single line before sending as an API request body or storing in a database field.
Normalizing Structure
Use Sort Keys to normalize JSON objects with consistent key ordering for cleaner diffs and code reviews.
Is my JSON data sent to your servers?
No. This tool runs entirely in your browser using JavaScript's native JSON.parse() API. Your data never leaves your device — nothing is transmitted to our servers at any point.
Why is my JSON showing as invalid?
Common causes include: trailing commas after the last item (not allowed in JSON), single quotes instead of double quotes around keys or strings, unquoted property names, or a missing closing bracket or brace. The error message will indicate the approximate position.
What is the difference between Format and Compact?
Format (pretty-print) adds line breaks and 2-space indentation to make JSON human-readable. Compact removes all whitespace to produce the smallest possible output — ideal for API payloads and storage.
Is there a file size limit?
There is no hard limit set by this tool. Very large files (10MB+) may slow down your browser since processing happens client-side, but typical API responses and config files process instantly.
Does this tool work offline?
Yes. Once the page has loaded, the formatter works without an internet connection because everything runs in your browser with no server calls required.
Can I format JSON with comments (JSON5)?
Standard JSON does not support comments, and this tool validates against the JSON specification. If your file contains comments (like in tsconfig.json), strip them first or use a JSON5-aware tool.