JSON Validator

Overview

• Checks whether the JSON you enter conforms to the standard JSON specification (RFC 8259).
• Unlike a formatter, the result is not formatted JSON but a validity verdict and, when invalid, the error details.
• Useful when you want to confirm that JSON data received from an external source is not broken, or when you need to pinpoint the cause of a syntax error.

Usage

1. Enter the JSON you want to validate into the text area.
2. Click the "Validate" button.
3. If the syntax is correct, "Valid JSON." is displayed; otherwise, the error details are shown.

Example

{"name": "Taro", "age": 20}

Valid JSON.

Use Cases

• Confirming that JSON data received from an external API or webhook is not broken before processing it
• Validating a manually edited configuration file (JSON format) before saving
• Checking JSON test data for syntax mistakes on the spot while authoring it

FAQ

Notes

• The result only judges syntactic correctness. It does not check the meaning of values or whether required fields are present.
• JSONC and JSON5, which allow comments or trailing commas, are outside the standard JSON specification and will be reported as errors.
• Validating very large JSON data (several MB or more) may make browser processing slow.