JSON to GraphQL Types Generator — Generate SDL Type Definitions

From JSON to GraphQL API in Seconds

Building a GraphQL API from an existing REST API or database? The hardest part is writing all the type definitions. Paste a sample JSON response and get a complete SDL schema including types, input types, and Query/Mutation boilerplate.

GraphQL Scalar Mapping

string → String
integer → Int
float → Float
boolean → Boolean
Field named id or _id → ID
null → nullable (no ! modifier)

What Gets Generated

type TypeName { ... } — Query return type
input TypeNameInput { ... } — Mutation argument type
type Query { get, list } — Sample query resolvers
type Mutation { create, update, delete } — Sample mutations

Frequently Asked Questions

What is a GraphQL input type?

An input type is used as an argument in mutations. Unlike regular types, input types can be passed as arguments and are typically used for create/update operations.

Does the generator support nested objects?

Yes. Nested JSON objects generate separate type and input blocks, referenced by the parent type.

Can I disable the Query and Mutation boilerplate?

Yes. Uncheck "Generate Query boilerplate" in the toolbar to output only the type definitions.

JSON to GraphQL: Generate Type Definitions & Schema Boilerplate