JSON Schema Validator

JSON Schema is a vocabulary that lets you validate the structure of JSON data. It defines what properties are allowed, what types they must be, which fields are required, and constraints like minimum/maximum values, string patterns, and array lengths. It's used in API documentation (OpenAPI/Swagger), form validation, configuration files, and data pipelines.

A schema is itself a JSON object with keywords like "type" (string, number, object, array, boolean, null), "properties" (defines object fields), "required" (mandatory fields), "minimum"/"maximum" (number constraints), and "pattern" (regex for strings). Schemas can be nested — an object property can itself have a schema with its own constraints.

Validation catches errors early — before data reaches your database, your API consumers, or your application logic. Instead of writing manual if/else checks for every field, you define the contract once as a schema and validate against it. This tool implements a lightweight client-side validator supporting the most common JSON Schema Draft 7 keywords.