JSON Validator
Check whether your JSON is valid, with the exact line and column of any error.
Common JSON mistakes
Trailing commas after the last item in an array or object, single quotes instead of double quotes, and unquoted object keys are all valid in JavaScript object literals but invalid in strict JSON.
Reading the error location
JavaScript's JSON.parse() reports a character position, not a line number. This tool converts that into a line and column so you can jump straight to the problem.
Common Mistakes to Avoid
Confusing a JS object literal with JSON
Solution:
JavaScript allows trailing commas, unquoted keys, and single quotes in object literals — none of these are valid in strict JSON. Copying a JS object directly often fails validation for this reason.
Not checking for duplicate keys
Solution:
JSON technically allows duplicate keys, but most parsers silently keep only the last one. This validator checks syntax validity, not for logically duplicate keys.
Frequently Asked Questions
It is the character index where parsing failed. This tool converts that into a line and column for easier navigation.
No — validation happens entirely in your browser.
Common JSON mistakes
Trailing commas after the last item in an array or object, single quotes instead of double quotes, and unquoted object keys are all valid in JavaScript object literals but invalid in strict JSON.
Reading the error location
JavaScript's JSON.parse() reports a character position, not a line number. This tool converts that into a line and column so you can jump straight to the problem.