✔ JSON Schema Validator

What is JSON Schema Validation?

JSON Schema is a vocabulary that allows you to annotate and validate the structure of JSON documents. It provides a standardized way to describe what a valid JSON document should look like, including the types of values, required fields, allowed ranges, string patterns, and the overall structure of nested objects and arrays. JSON Schema Draft 7 is one of the most widely adopted versions, supported by tools and libraries across virtually every programming language.

Validation is the process of checking whether a given JSON document conforms to a specific schema. When you validate JSON data against a schema, the validator walks through every rule defined in the schema and compares it to the corresponding part of the data. If the data satisfies all constraints, validation passes. If not, the validator produces a list of errors that describe exactly where and why the data does not conform. This is invaluable during API development, data pipeline testing, configuration management, and any scenario where you need to guarantee that incoming or outgoing JSON has the correct shape.

This free online tool implements a comprehensive JSON Schema Draft 7 validator that runs entirely in your browser. It supports core keywords like type, properties, required, items, enum, minimum, maximum, minLength, maxLength, pattern, format, anyOf, oneOf, allOf, not, additionalProperties, and local $ref references. It also validates common string formats including email, URI, date, date-time, IPv4, and IPv6.

How to Use This Tool

1. Paste or type your JSON Schema into the left panel. The schema must be a valid JSON object that follows the JSON Schema Draft 7 specification.
2. Paste or type the JSON data you want to validate into the right panel.
3. Click the "Validate" button to check whether the data conforms to the schema. You can also click "Sample (Valid)" to load a working example or "Sample (Errors)" to load an example that intentionally fails validation.
4. Review the results below the editors. A green checkmark means the data is valid. A red indicator shows all validation errors with the exact path to each failing property, the expected constraint, and the actual value found.
5. Click "Format Both" to beautify the JSON in both panels, or "Schema Tree" to view the schema structure as a collapsible tree.

Key Features

• Comprehensive Draft 7 Support - Validates against all major JSON Schema Draft 7 keywords including type, properties, required, items, enum, pattern, format, anyOf, oneOf, allOf, not, additionalProperties, and local $ref references.
• Detailed Error Reporting - Every validation error includes the path to the failing property, the expected type or constraint, and the actual value found. All errors are collected rather than stopping at the first failure.
• Format Validation - Checks common string formats such as email addresses, URIs, dates, date-time strings, IPv4 addresses, and IPv6 addresses using standards-compliant regular expressions.
• Schema Tree View - Displays your schema as a collapsible tree, making it easy to understand the structure at a glance, see which fields are required, and review constraints on each property.
• 100% Client-Side - All validation happens in your browser. Your schemas and data are never uploaded, stored, or shared with any third party. The tool works offline after the page loads.

Frequently Asked Questions

What is the difference between JSON validation and JSON Schema validation?

JSON validation checks whether a string is well-formed JSON, meaning it follows the basic syntax rules of the JSON format. JSON Schema validation goes further: it checks whether a valid JSON document conforms to a specific structural contract defined by a schema. For example, a JSON document might be syntactically valid but still fail schema validation because a required field is missing or a value has the wrong type.

What JSON Schema draft versions are supported?

This tool implements JSON Schema Draft 7 keywords. Many Draft 4 and Draft 6 schemas will also validate correctly since Draft 7 is largely backward-compatible. However, newer draft features from Draft 2019-09 or Draft 2020-12, such as $dynamicRef or prefixItems, are not supported.

Does this tool support $ref references?

Yes, local $ref references are fully supported. You can define reusable schema fragments in a definitions block and reference them elsewhere in your schema using {"$ref": "#/definitions/YourDefinition"}. Remote references that point to external URLs are not supported since the tool runs entirely offline in your browser.

Why does validation show multiple errors at once?

This validator intentionally collects all errors rather than stopping at the first failure. This gives you a complete picture of every place where the data does not match the schema, so you can fix all issues in one pass instead of fixing one error at a time and re-running the validator repeatedly.