How to Use the JSON Validator

Paste your JSON data into the editor above and click "Validate". The validator will instantly tell you whether your JSON is syntactically correct. If there are errors, you will see a detailed message pointing to the exact location of the problem.

What is JSON Validation?

JSON validation checks whether a string conforms to the JSON specification (RFC 8259). Valid JSON must follow strict rules: strings must be double-quoted, trailing commas are not allowed, keys must be unique strings, and values must be one of the six permitted types: string, number, object, array, boolean, or null.

Even small mistakes — a missing comma, an extra bracket, or a single-quoted string — will cause JSON parsers to fail. Our validator catches these errors immediately and reports them in plain English so you can fix them quickly.

Common JSON Errors

Trailing commas — {"a": 1,} is invalid. Remove the last comma.
Single quotes — JSON requires double quotes. {"key": 'value'} will fail.
Unescaped characters — Newlines and tabs inside strings must be escaped as \n and \t.
Missing brackets — Every opening { or [ must have a matching closing bracket.
Undefined / NaN — These JavaScript values are not valid JSON.

Understanding the Stats

When your JSON is valid, the validator shows three statistics:

Top-level keys — The number of keys at the root level of an object.
Max depth — How deeply nested the structure is. A flat object has depth 1; an object inside an object has depth 2, and so on.
Array items — If the root value is an array, this shows how many items it contains.

FAQ

Is my data safe?

Yes. All validation runs entirely in your browser using JavaScript. Your data never leaves your device and is never sent to a server.

Does this validate JSON Schema?

This tool validates JSON syntax only — it checks that the text is well-formed JSON. It does not validate against a JSON Schema definition. For schema validation you would need a dedicated JSON Schema validator.

What is the maximum input size?

The validator handles inputs up to 1MB. Larger inputs may cause performance issues in the browser.