How to use
- Paste or type JSON into the input box.
- Select Validate, or press Ctrl+Enter (⌘+Enter on Mac) in the input box.
- If the JSON is valid, the result shows the type of its top-level value.
- If it is invalid, fix the reported line and column and validate again.
What the validator checks
Input is checked with your browser's built-in JSON parser, following the JSON standard (RFC 8259). Comments, trailing commas, single quotes, unquoted keys, and values like NaN or undefined are reported as errors.
The validator only answers whether the input is valid JSON. It never changes, reformats or repairs your input. To pretty-print valid JSON, use the JSON Formatter.
Error locations
When the browser reports where the error is, the validator shows the line and column so you can find it quickly. Some errors are reported without a position; in that case only the parser's message is shown.
Limits
Input is limited to 5,000,000 characters. The validator checks syntax only; it does not check your data against a JSON Schema.
FAQ
- Is my JSON uploaded?
- No. Validation runs entirely in your browser. Your JSON is not sent to a server, not stored, and not added to the page URL.
- Are duplicate keys an error?
- No. The JSON standard allows duplicate keys and the browser's parser accepts them, so the validator reports such input as valid.
- Does valid JSON mean my data is correct?
- No. Valid means the syntax follows the JSON standard. Whether the data has the fields and types your application expects is a separate check (JSON Schema validation).