JSON Schema Validator: Validate Data Against Draft-07 Schemas

JSON Schema Validation vs JSON Syntax Validation

There are two levels of JSON validation:

1. Syntax validation — Is this text valid RFC 8259 JSON? (Does it parse?)
2. Schema validation — Does this JSON object match an expected structure? (Do all required fields exist with the right types?)

JSON Schema validation is the more powerful of the two — it can enforce field types, required properties, string formats, numeric ranges, and array constraints.

What JSON Schema Draft-07 Can Validate

• required — enforce mandatory fields
• type — string, number, integer, boolean, object, array, null
• format — email, date-time, uri, uuid
• minimum / maximum — numeric range constraints
• minLength / maxLength — string length constraints
• pattern — regex pattern matching
• enum — allowed value enumeration

// JSON Schema (Draft-07)
{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "required": ["name", "email", "age"],
  "properties": {
    "name":  { "type": "string", "minLength": 1 },
    "email": { "type": "string", "format": "email" },
    "age":   { "type": "integer", "minimum": 0, "maximum": 150 }
  }
}

// ✅ Valid Data
{ "name": "Alice", "email": "a@example.com", "age": 28 }

// ❌ Invalid Data (3 errors)
{ "name": "", "email": "not-an-email", "age": -5 }
// Error 1: name must be at least 1 character
// Error 2: email must match format "email"
// Error 3: age must be >= 0