JSON Validator -- Check Syntax
Validate JSON syntax and find errors with line numbers. Free online JSON validator that checks your JSON instantly in the browser. No data sent to any server.
Frequently Asked Questions
How does JSON validation work?
This tool uses JSON.parse() to attempt parsing your input. If the JSON is valid, it confirms success and shows the parsed structure. If there are errors, it displays the error message with an approximate line number to help you locate and fix the issue.
What are common JSON syntax errors?
Common JSON errors include: trailing commas after the last element, single quotes instead of double quotes, unquoted keys, missing commas between elements, and using undefined or NaN values. JSON requires strict syntax compared to JavaScript object literals.
Can I validate large JSON files?
Yes. This tool runs entirely in your browser and can handle JSON files of any size that your browser's memory allows. There is no server-side limit. For very large files (100MB+), parsing may take a few seconds.
Does this tool fix invalid JSON?
This tool identifies and reports errors but does not automatically fix them. It shows the error message and position so you can make the correction yourself. Common fixes include adding missing commas, replacing single quotes, and removing trailing commas.