JSON Schema

JSON Schema acts as a blueprint for your JSON data. It's a powerful tool used to describe and validate the structure of JSON objects. By defining a schema, you ensure that any incoming data meets expected formats and business rules — which is especially important in API development, form validation, and configuration files.

With JSON Schema, you can:

• Specify required and optional fields.
• Enforce strict data types such as string, number, boolean, or array.
• Apply constraints like minimum/maximum values, string length limits, regex patterns, and value enums.
• Define the expected structure of nested objects and arrays.
• Enable automatic validation in tools and programming libraries.

Example Schema

The following JSON Schema defines a simple "Product" object with two required fields: productId (a number) and productName (a string).

{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "title": "Product",
    "type": "object",
    "properties": {
      "productId": { "type": "number" },
      "productName": { "type": "string" }
    },
    "required": ["productId", "productName"]
  }

JSON Schema is widely supported in tools like OpenAPI, AJV (Another JSON Schema Validator), and many backend languages such as Python, Node.js, and Java. It's a foundational technology in modern backend and frontend data validation.