Free JSON Schema Validator – Validate JSON Against Schema

Paste your JSON and a JSON Schema and instantly see validation results. Catches missing required fields, wrong types, pattern errors, and more — all in your browser, no server.

JSON Input

JSON Schema

Validation Result

What is JSON Schema Validation?

Ever shipped an API only to find out the payload was missing a required field, or a value was the wrong type? That's exactly what JSON Schema is designed to prevent. It's a standard (defined in JSON Schema Draft specifications) for describing the structure and constraints of JSON data. This tool lets you paste both a JSON document and a schema, and instantly tells you whether the data is valid — pointing to exactly which fields fail and why.

This tool validates your JSON against a JSON Schema definition, checking required fields, data types, string patterns, numeric ranges, and more. If you need a full-featured validator library for production code, AJV (Another JSON Validator) is the most widely used JavaScript implementation.

How to Use

1

Enter your JSON

Paste the JSON data you want to validate in the left panel.

2

Enter your JSON Schema

Paste the JSON Schema definition in the right panel. The schema defines what the valid JSON structure should look like.

3

See validation results

The tool automatically validates as you type (debounced). The output panel shows whether the JSON is valid or lists all validation errors with field paths.

Validation Example

Example: Validate a user object

JSON document:

{
  "name": "Alice",
  "age": 30,
  "email": "[email protected]"
}

JSON Schema:

{
  "type": "object",
  "required": ["name", "age", "email"],
  "properties": {
    "name": { "type": "string" },
    "age": { "type": "integer", "minimum": 0 },
    "email": { "type": "string", "format": "email" }
  }
}

Frequently Asked Questions

How do I validate JSON against a schema online?

Paste your JSON into the left panel and your JSON Schema into the right panel on this page. The tool validates automatically as you type and shows either a pass or a list of errors with field paths.

What JSON Schema keywords does this validator support?

Supported keywords include: type, required, properties, minLength, maxLength, minimum, maximum, pattern, and enum. These cover the vast majority of real-world validation use cases.

Is my JSON data sent to a server when I validate?

No. All validation runs entirely in your browser. Your JSON and schema are never sent anywhere — making this safe to use with sensitive API payloads or config files.

Which JSON Schema draft versions does this tool support?

This tool supports core validation keywords from JSON Schema Draft 4, 6, 7, and 2019-09. That covers type, required, properties, minimum, maximum, pattern, enum, and more. For full Draft 2020-12 support with all new features, check out the AJV library for production use.

Related Tools

JSON Formatter JSON Validator JSON Schema Generator JSON Minifier

References: JSON Schema | JSON.org