JSON Validator
Check JSON syntax instantly and find errors without uploading your data.
Paste, type, or upload a JSON document to validate it.
Questions answered
JSON Validator FAQs
What does a JSON validator check?+
A JSON validator checks whether a document follows JSON syntax, including double-quoted strings and keys, correctly matched braces and brackets, valid values, and required commas. It reports the approximate line and column when parsing fails.
Is this JSON validator private?+
Yes. Validation runs locally in your browser with the built-in JSON parser. Your pasted text and uploaded files are not sent to jsontoyaml.net or an external validation service.
Why is my JSON invalid?+
Common causes include trailing commas, single-quoted strings, unquoted property names, missing commas, mismatched braces or brackets, comments, and values such as undefined or NaN that are valid in JavaScript but not valid JSON.
Can I validate a JSON file?+
Yes. Select Upload and choose a .json file. The file is read locally, validated immediately, and never uploaded to the server.