JSON Validator
Validate, format, and beautify your JSON code. Detect syntax errors, fix formatting issues, and minify JSON data for development.
About
JSON (JavaScript Object Notation) is the standard data interchange format on the web. However, it is strict: a missing comma, a trailing comma, or unquoted keys can break applications. This tool validates your JSON string against the standard RFC 8259 specifications.
Use this validator to debug API responses, configure files, or clean up messy data structures. It provides instant feedback on syntax errors and helps you pretty-print code for readability.
syntax checker
code formatter
debugging
Formulas
The validation process follows a strict algorithmic parsing sequence:
- Step 1. Accept raw text string from user input.
- Step 2. Attempt to parse using standard JSON engine.
- Step 3. IF Success: Re-serialize the object with 2-space indentation (Pretty Print).
- Step 4. IF Fail: Catch the exception and extract the character position and error message to display to the user.
Reference Data
| Common Error | Description |
|---|---|
| Unexpected token | Often caused by a trailing comma after the last item. |
| Unterminated string | Missing a closing quote marks inside the data. |
| Expected property name | Keys must be wrapped in double quotes (e.g., "key":). |
| Unexpected end of input | Missing a closing brace } or bracket ]. |
Frequently Asked Questions
JSON is not identical to JavaScript objects. JSON requires all keys to be in double quotes (e.g., {"a": 1}), whereas JS allows {a: 1}. It also forbids trailing commas.
No. All validation and formatting happen locally in your browser via JavaScript. No data is sent to any server.
Minification removes all unnecessary whitespace and newlines from the JSON, making the file size smaller for efficient network transmission.