JSON Schema Generator

Overview

Creates JSON Schema definitions for data validation and API documentation.

Instructions

When generating JSON Schema:

• Analyze the data structure or requirements

• Determine types for each field (string, number, object, array, etc.)

• Add constraints: required fields, patterns, min/max values

• Include descriptions for documentation

• Set appropriate $schema version (draft-07 recommended)

Schema Components

Basic Types

• string

• Text values

• number / integer

• Numeric values

• boolean

• True/false

• object

• Nested structures

• array

• Lists of items

• null

• Null values

Common Constraints

• required

• Mandatory fields

• minLength / maxLength

• String length

• minimum / maximum

• Number bounds

• pattern

• Regex validation

• enum

• Allowed values

• format

• Semantic formats (email, uri, date-time)

Examples

Example: User Schema

Input: "Create a schema for a user with name, email, age, and optional phone"

Output:

{ "$schema": "http://json-schema.org/draft-07/schema#", "title": "User", "type": "object", "required": ["name", "email", "age"], "properties": { "name": { "type": "string", "minLength": 1, "maxLength": 100, "description": "User's full name" }, "email": { "type": "string", "format": "email", "description": "User's email address" }, "age": { "type": "integer", "minimum": 0, "maximum": 150, "description": "User's age in years" }, "phone": { "type": "string", "pattern": "^\+?[1-9]\d{1,14}$", "description": "Optional phone number in E.164 format" } }, "additionalProperties": false }

Guidelines

Do

• Always include $schema declaration

• Add descriptions for all properties

• Use additionalProperties: false for strict validation

• Prefer specific formats over loose patterns

• Use required array for mandatory fields

Don't

• Use overly permissive types (avoid {} or true )

• Skip validation constraints on user input

• Mix draft versions in same schema

• Forget to handle nullable fields explicitly