JSON Schema Validator
Validate JSON against a JSON Schema
DevToolKit's JSON Schema Validator checks JSON data against a JSON Schema definition with detailed error reporting. It supports Draft 07 and 2020-12, powered by AJV. Runs entirely in your browser — no data uploaded. Free with no signup required.
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What is a JSON Schema Validator?
A JSON Schema Validator checks whether a piece of JSON data conforms to a defined JSON Schema — a vocabulary for annotating and validating the structure of JSON documents. JSON Schema lets you declare the expected types, required fields, value constraints, and nested object structures for any JSON payload, similar to how an XML Schema (XSD) defines the shape of XML documents. It is widely used in API development to validate request and response payloads against a contract, in configuration management to catch invalid settings before deployment, and in data pipelines to enforce quality gates on ingested data. Key schema keywords include 'type' (data type constraint), 'properties' (object field definitions), 'required' (mandatory fields), 'items' (array element schemas), 'pattern' (regex validation), '$ref' (reusable schema references), and conditional keywords like 'if/then/else'. This tool is powered by AJV, the fastest JSON Schema validator for JavaScript, and primarily targets Draft 07 — the most broadly adopted specification version. All validation runs entirely in your browser, so your data and schemas are never transmitted to any server, making it safe for proprietary APIs and sensitive configuration files.
How to Use the JSON Schema Validator
- Paste your JSON data in the left panel and your JSON Schema in the right panel.
- Or click 'Load Sample' to try with pre-built examples (User, Product, API Response).
- Click 'Validate' to check if the data conforms to the schema.
- Review the results — green for valid, red for errors with detailed paths and messages.