JSON Schema to GraphQL Schema Generator

Transform JSON Schema definitions and required constraints into production-ready GraphQL SDL.

At a glance

JSON Schema to GraphQL Schema Generator is a free developer utility that transforms JSON Schema Draft-04 through 2020-12 specifications into GraphQL Schema Definition Language (SDL). It resolves $defs and definitions references, maps required arrays to non-null types, and synthesizes operations 100% client-side in browser memory.

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100% Client-Side JSON Schema to GraphQL Schema Generator

Zero Server Uploads

Transform JSON Schema models, $defs definitions, required nullability constraints, and enums into strongly-typed GraphQL SDL schemas, operations, and input types.

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Required Array Nullability

Accurately inverts JSON Schema nullability semantics: fields in required: [...] map to non-null Type!, while omitted properties remain cleanly nullable.

$defs & $ref Resolution

Recursively resolves local JSON pointers like #/$defs/Model and #/definitions/Item into top-level GraphQL types, enums, and unions.

Instant CRUD Synthesis

Generates production-grade Apollo / GraphQL Yoga root Query, Mutation, and filtered input types with primary keys automatically excluded from Create DTOs.

Why Use This JSON Schema to GraphQL Schema Generator?

100% Client-Side Privacy: Your JSON Schema models never leave your device or touch any server.
Smart Reference Resolution: Recursively resolves $defs and definitions into standalone GraphQL types, enums, and unions.
Required Array Nullability: Accurately maps JSON Schema required arrays to non-null GraphQL ! field modifiers.
CRUD Operations & Inputs: Automatically synthesizes root Query, Mutation, and Create/Update input objects.

How to Use JSON Schema to GraphQL Schema Generator

1

Input JSON Schema

Paste your JSON Schema object into the editor or upload a .json file.

2

Configure Options

Toggle root queries, mutations, and input types generation as needed.

3

Copy or Download

Copy the generated GraphQL SDL or download it as schema.graphql.

JSON Schema to GraphQL Conversion example

Converts a JSON Schema User model into GraphQL SDL with non-null id and name, nullable bio, and root queries.

JSON Schema Source 
{
  "title": "User",
  "type": "object",
  "properties": {
    "id": { "type": "string", "format": "uuid" },
    "name": { "type": "string" },
    "bio": { "type": "string" }
  },
  "required": ["id", "name"]
}
Generated GraphQL SDL Processed 
type User {
  id: ID!
  name: String!
  bio: String
}

type Query {
  users: [User!]!
  user(id: ID!): User
}

Technical Specifications & Engine Details

Technical specifications and engine details for JSON Schema to GraphQL Schema Generator
Specification Details
Supported JSON Schema Formats Draft-04, Draft-07, Draft 2019-09, Draft 2020-12, OpenAPI 3.0/3.1
Execution Mode 100% Client-Side In-Browser (Zero server latency)
Nullability Mapping Properties in required array → GraphQL !, omitted → unadorned
Generated Output GraphQL SDL (Types, Enums, Unions, Queries, Mutations, Inputs)
Maintained by Pragyan Pahadi

100% Client-Side Privacy Guarantee

Your files remain strictly on your local device. Zero data is transmitted to external servers.

Frequently Asked Questions

How does JSON Schema nullability map to GraphQL SDL?
Properties specified in the parent required array map to non-null GraphQL fields (e.g. name: String!). Properties omitted from required remain unadorned and nullable (e.g. bio: String). Types defined with type: [string, null] also map to nullable GraphQL fields.
How are JSON Schema definitions and $defs resolved?
The generator parses definitions and $defs objects into standalone GraphQL object types, enums, or unions. Any property with $ref pointing to #/$defs/Name or #/definitions/Name references that type directly.
How are formats like date-time and uuid handled?
String properties with format: date-time or format: date map to DateTime (emitting top-level scalar DateTime). Properties with format: uuid or named id map to GraphQL ID scalar.
Is any JSON Schema data sent to external servers?
No. All JSON parsing, reference resolution, and GraphQL SDL generation execute 100% locally in your browser memory with zero network requests and complete data privacy.

Methodology

This tool runs entirely in your browser. The example above shows a representative input and the result it produces.

Last updated .

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