JSON Validator Online — Check JSON Syntax
Validate JSON syntax online and identify parsing errors in API payloads, configuration files and copied data without uploading the content.
About this tool
The JSON validator checks whether the supplied text can be parsed as standards-compliant JSON. It is useful when an API rejects a request, a configuration file will not load, or copied JSON contains a small syntax mistake.
How to use
- Paste the JSON text you want to check.
- Select Validate JSON to parse the complete document.
- Use the reported syntax details to correct the input and validate it again.
Features
- Checks complete objects, arrays and primitive JSON values.
- Reports parser error details for invalid input.
- Runs instantly without an account or server upload.
Common use cases
- Troubleshoot rejected REST or GraphQL request bodies.
- Check package, deployment or application configuration.
- Verify JSON copied from logs, spreadsheets or documentation.
Common issues and tips
- Missing commas, braces or quotation marks often make the parser report an error near the following token.
- A JSON document cannot contain comments, NaN, Infinity or undefined.
Privacy
Validation is performed locally in your browser. Your JSON is not sent to our servers.
Frequently asked questions
What makes JSON valid?
Valid JSON follows its grammar exactly: quoted string keys, supported value types, balanced brackets and no trailing commas or comments.
Does this validator check a JSON Schema?
No. It checks JSON syntax only; it does not validate required fields, data types or business rules from a JSON Schema.
Why is the reported position after the real mistake?
A parser can only detect a problem when the next token becomes impossible, so the missing comma or quote may be slightly earlier.