ConverterJSON Validator
Check whether text is one complete JSON value. The validator separates syntax validity from schema, business-rule, and API acceptance questions.
Validate JSON Syntax
What A Result Means
| Result | Meaning | Not established |
|---|---|---|
| Syntax-valid JSON | One complete RFC 8259 value parsed | Schema, required fields, authorization |
| Duplicate-name warning | Syntax parsed but member names repeat | How a destination resolves duplicates |
| Numeric warning | Number grammar is valid | Exact support in every consumer |
Diagnostics And Implementation Limits
Errors identify the line, column, and character offset available from the tokenizer. A leading BOM marker is ignored with a warning; trailing material after the JSON value is rejected.
Nesting is limited to 200 levels and input to 1,000,000 characters to protect the browser. A number such as 1e400 can be valid JSON syntax even though JavaScript Number cannot materialize it as a finite value.
Common Syntax Failures
- Trailing commas after the final member or item.
- Comments or single-quoted strings copied from JavaScript.
- NaN and Infinity, which are not JSON numbers.
- A second value or other non-whitespace text after the first value.
Questions About This Tool
Yes. JSON text can contain any serialized value, including null, false, a number, or a string.
No. API acceptance also depends on schema, fields, authentication, authorization, and application rules.
Not automatically. They are reported as an interoperability warning because receiving software handles them differently.