How to check if JSON is invalid?

To check if JSON is invalid, use validation tools that parse and analyze the syntax. Our JSON Editor at jsonconsole.com/json-editor instantly validates JSON, displaying error messages for any syntax issues. Try parsing the JSON in code using try-catch blocks—JSON.parse() throws errors for invalid JSON with descriptions of the problem. Invalid JSON typically has missing commas, incorrect quotes (single instead of double), trailing commas, unmatched brackets or braces, or invalid data types. Validator tools highlight the exact line and character where errors occur. In browser developer tools, the Network tab shows JSON parsing errors for API responses. Signs of invalid JSON include parsers rejecting the data, unexpected behavior when loading configuration files, or API requests failing. Always validate JSON before deployment or sending to production systems. Our validator catches errors immediately, providing specific guidance on what is wrong and how to fix it.