JSON Validator
Check whether text is valid JSON and find the exact line and column of any error.
Data
Validate
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Strict rules
- JSON, not JavaScript: Keys and strings need double quotes; comments, trailing commas, NaN and Infinity are not allowed. Some tools accept comments (JSONC, JSON5), but strict parsers, as used by most APIs, do not.
- Helpful messages: Common mistakes, such as single quotes or comments, get a message that names the problem directly.
- More than yes or no: Valid JSON is described: object or array, number of entries and nesting depth. Duplicate keys are listed as warnings.
Frequently asked questions
Does it check a JSON schema?
No. It checks syntax only: whether the text is well-formed JSON, not whether the data has the fields a program expects.
What does "nesting depth" mean?
How many objects or arrays are inside each other at the deepest point. A flat list of values has depth 1.