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JSON & DataAvailableFreeRuns locally

JSON Validator

Check JSON syntax and identify malformed data quickly.

Validate JSON syntax

Paste JSON and check its syntax locally in your browser.

Your JSON is validated locally in your browser and is not sent to a server.

Overview

What is a JSON validator?

A JSON validator checks whether text follows the JSON grammar. It helps identify syntax problems before JSON is used in an API request, configuration file, test fixture, or application.

This tool is a JSON syntax checker. It uses the browser JSON parser and reports the parsing error when the input is invalid.

Steps

How to validate JSON

  1. Paste JSON into the JSON Input field.
  2. Select Validate JSON.
  3. Review the validation result and any reported syntax error.
  4. Fix the error, then validate the JSON again.

Troubleshooting

Common JSON syntax errors

  • Trailing commas: the final property or array item cannot end with a comma.
  • Missing quotes: object property names must use double quotes.
  • Single quotes: JSON strings require double quotes, not single quotes.
  • Missing values: every property name must be followed by a valid JSON value.
  • Unmatched braces or brackets: every opening delimiter needs a matching closing delimiter.

Examples

Valid and invalid JSON examples

Valid JSON

{
  "name": "Orbilyra",
  "valid": true
}

Invalid JSON

{
  "name": "Orbilyra",
  "valid": true,
}

Comparison

JSON Validator vs JSON Formatter

JSON Validator focuses on checking syntax and exposing parsing errors. JSON Formatter focuses on beautifying and minifying valid JSON.

If your JSON is valid and you want to make it easier to read or more compact, use theJSON Formatter.

Scope

JSON syntax vs JSON Schema

Syntax validation checks whether JSON follows the JSON grammar. Schema validation checks whether parsed data matches a specified structure, data type, and set of rules.

This tool validates syntax only. It does not validate JSON Schema, API contracts, or business-specific field requirements.

Workflows

When to validate JSON syntax

  • Check a request body before sending it to an API.
  • Diagnose copied configuration data that fails to parse.
  • Find trailing commas, invalid quotes, missing values, or unmatched delimiters.
  • Confirm syntax before applying separate JSON Schema or business-rule validation.

FAQ

Frequently asked questions

What is a JSON validator?

A JSON validator checks whether text follows JSON syntax, including valid quoting, values, commas, braces, and brackets.

Does this validator upload my JSON?

No. Validation happens locally in your browser, and this tool does not send your JSON to a server.

What JSON errors can this tool detect?

It detects syntax errors reported by the browser JSON parser, such as trailing commas, invalid quotes, missing values, and unmatched braces or brackets.

Does this validate JSON Schema?

No. This tool validates JSON syntax only. It does not check JSON Schema, API contracts, or business field rules.

What is the difference between a JSON validator and formatter?

A validator focuses on syntax correctness and parsing errors. A formatter focuses on making valid JSON readable or compact.

Why is a trailing comma invalid in JSON?

The JSON grammar does not allow a comma after the final property in an object or the final item in an array.