JSON Schema Generator

Generate JSON Schema definitions from example JSON objects, descriptions, or TypeScript types.

Use this prompt — free See example output

The Prompt

(2 messages)

System

You are a JSON Schema expert. Generate valid JSON Schema (draft 2020-12) from the provided input.

Rules:
- Infer types, required fields, and constraints from the input
- Add descriptive "description" fields for every property
- Use appropriate string formats (email, uri, date-time, uuid) when the data suggests it
- Add sensible constraints: minLength, maxLength, minimum, maximum, pattern where applicable
- Mark fields as required if they appear consistently or are clearly essential
- If generating from an example, note any assumptions about optionality in the output

User

Generate a JSON Schema from the following:

Input type: {{input_type}}

Input:
{{input}}

Variables

Fill in these inputs to customize your output:

{{input_type}}

Example: example JSON object

{{input}}

Example: { "id": "usr_abc123", "email": "alex@example.com", "name": "Alex Chen", "role": "admin", "created_at": "2026-01-15T10:30:00Z", "settings": { "theme": "dark", "notifications": true, "language": "en" } }

Example Output

Here's what this prompt generates with the sample inputs:

Sample outputgpt-4.1

{
  "schema": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "title": "User",
    "properties": {
      "id": {
        "type": "string",
        "description": "Unique user identifier with 'usr_' prefix.",
        "pattern": "^usr_[a-zA-Z0-9]+$"
      },
      "email": {
        "type": "string",
        "format": "email",
        "description": "User's email address."
      },
      "name": {
        "type": "string",
        "description": "User's display name.",
        "minLength": 1,
        "maxLength": 255
      },
      "role": {
        "type": "string",
        "enum": ["admin", "member", "viewer"],
        "description": "User's role in the workspace."
      },
      "created_at": {
        "type": "string",
        "format": "date-time",
        "description": "ISO 8601 timestamp of when the user was created."
      },
      "settings": {
        "type": "object",
        "description": "User preferences.",
        "properties": {
          "theme": {
            "type": "string",
            "enum": ["light", "dark", "system"],
            "description": "UI theme preference."
          },
          "notifications": {
            "type": "boolean",
            "description": "Whether email notifications are enabled."
          },
          "language": {
            "type": "string",
            "description": "Preferred language as ISO 639-1 code.",
            "pattern": "^[a-z]{2}$"
          }
        },
        "required": ["theme", "notifications", "language"]
      }
    },
    "required": ["id", "email", "name", "role", "created_at"]
  },
  "assumptions": [
    "role enum values inferred as admin/member/viewer — adjust based on your actual roles",
    "theme enum includes 'system' as a common default — verify against your options",
    "All top-level fields except settings are marked as required since they appear essential"
  ]
}