JSON to GraphQL Schema

About This Tool

Generates a GraphQL SDL type definition from a sample JSON payload, inferring scalars (ID/Int/Float/Boolean/String) field by field, and optionally attaches Query and Mutation type stubs built around that root type's name.

Query/Mutation stubs are schema shape only, not a working resolver or server, pair this with your own backend. For a TypeScript interface or Go struct from the same JSON instead, see JSON to TypeScript or JSON to Go Struct.

Key Features

• Root Type Name field: names the generated type and feeds the Query/Mutation stub names.
• Independent Query/Mutation toggles: generate either, both, or neither type.
• Nullable Fields toggle: switches every field between a strict ! non-null marker and optional.
• Recursive nested types: each nested JSON object becomes its own named GraphQL type.
• Download as .graphql: exports the schema to a file named after the root type.

Example

With Root Type Name User and both Query and Mutation types enabled:

{
  "id": "e4a7a8d1-5912-4c22-b5e1-88f192aa0123",
  "username": "alex_rivera",
  "is_admin": true
}

produces:

type User {
  id: ID!
  username: String!
  is_admin: Boolean!
}

type Query {
  getUser(id: ID!): User
  listUsers(limit: Int, offset: Int): [User!]!
}

type Mutation {
  createUser(input: UserInput!): User!
  deleteUser(id: ID!): Boolean!
}