Free JSON validator and beautifier tool. Learn how to check your JSON for syntax errors, format it with proper indentation, and debug API responses.
JSON is everywhere in modern web development - API responses, configuration files, data storage. But one missing comma or an extra bracket and your entire application breaks. A JSON validator catches these errors instantly.
Our JSON Validator and Beautifier checks your JSON syntax and formats it cleanly.
Common JSON Mistakes
- Trailing commas - JSON does not allow a comma after the last item in an array or object
- Missing quotes - All property names must be in double quotes
- Single quotes - JSON requires double quotes, not single quotes
- Comments - JSON does not support comments (unlike JSONC or JSON5)
- Trailing garbage - Extra text after the closing brace or bracket
When to Use a Validator
After editing a config file (like package.json, tsconfig.json, or a cloud provider config). When debugging an API response that won't parse. Before committing a JSON file to version control. When copying JSON from one system to another.
The beautifier also formats compressed or minified JSON into readable, indented output - essential for debugging large API responses.