JSON Validator

Valid is not the same as expected

Any single JSON value is a valid document: "hello", 42, and null all pass, as RFC 8259 allows. An API that expects an object will still reject them, which is why the root type and entry count are shown. If you expected an object with 20 keys and see a string, the payload was probably JSON encoded twice and needs parsing again.

Errors you cannot see

When the reported position points at what looks like a normal space or quote, the character is probably not what it seems. Word processors and chat apps swap straight quotes for curly ones (“ and ”), which JSON does not accept, and text copied from web pages can carry non-breaking or zero-width spaces. A byte-order mark at the very start also fails. The Unicode inspector shows each character's code point so the culprit is easy to find.

Checking files in scripts

For many files or a build step, validate on the command line. jq empty file.json prints nothing for valid JSON and exits with an error code otherwise, and python3 -m json.tool file.json does the same without extra installs. Both report the line and column of the first error. Text from a language model or a JavaScript file that fails for trailing commas or comments can be fixed with the JSON repair tool.

How to use it

1. Paste JSON into the editor.
2. Choose Validate JSON.
3. Review the validity and root summary.

Privacy & limitations

Your JSON stays in the browser. Syntax validity does not guarantee that data matches an application schema.