About JSON Validator
Check whether a document is valid JSON and, when it is not, see exactly where the parser gave up — with the offending line quoted and a caret under the failing column.
Errors you can act on
Browsers report a character offset, which is useless in a thousand-line file. This tool converts that offset into a line and column and prints the surrounding lines, so a trailing comma or unquoted key takes seconds to find.
Frequently asked questions
- What are the most common JSON syntax errors?
- Trailing commas after the last element, single quotes instead of double quotes, unquoted property names, and comments — none of which are legal JSON, even though JavaScript accepts them.
- Does it validate against a JSON Schema?
- Not yet. This checks syntax only. Schema validation, which checks types and required fields, is planned as a separate tool.