GraphQL to TypeScript

GraphQL schemas describe types directly. The job is mapping SDL types to TypeScript and matching your client operations to the right subset. This guide compares the main tools and shows the workflow we recommend for production codebases.

Tooling landscape

Tool	Approach	Best for
GraphQL Code Generator	Codegen at build time	Apollo, urql, plain fetch — the broadest plugin ecosystem.
gql.tada	Type-level inference from inline strings	No codegen step; types fall out of template literals automatically.
Houdini	Framework-integrated client + codegen	SvelteKit and Solid Start projects.
Relay	Compiler + runtime, Facebook-grade	Big React apps where fragment-level data colocation matters.

Mapping SDL types to TypeScript

schema.graphql

type User {
  id: ID!
  name: String!
  email: String
  posts: [Post!]!
}

type Post {
  id: ID!
  title: String!
}

schema.ts (generated)

export interface User {
  id: string;
  name: string;
  email: string | null;
  posts: Post[];
}

export interface Post {
  id: string;
  title: string;
}

Notice the patterns: ! in SDL becomes non-nullable in TS, bare types become | null, and lists become arrays. Custom scalars (DateTime, JSON) need a mapping config.

Recommended workflow

Install @graphql-codegen/cli and the typescript plugins.
Create a codegen.ts pointing at your schema and operations.
Generate operation-specific types alongside the schema types so each query gets a precise return type.
Wire up codegen --watch during development, run once in CI.
For runtime validation of mutation inputs, generate Zod schemas alongside — or feed the generated types through our TypeScript → Zod converter.

Related tools

OpenAPI to TypeScript ›

Same idea, for REST APIs described by OpenAPI 3.

TypeScript to Zod ›

Add runtime validation on top of generated types.

JSON to TypeScript ›

Inference from a sample response when you have no schema.

Migrate the rest of your client

GraphQL types describe queries. JavaScriptConverter handles the JavaScript that calls them.

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