Installation

Prerequisites

Effect GraphQL requires:

• Node.js 24 or later
• TypeScript 5.0 or later (for full type inference)

Install Dependencies

npm install @effect-gql/core effect graphql

This installs:

• @effect-gql/core - The core library
• effect - The Effect runtime and Schema library
• graphql - GraphQL.js for schema execution

TypeScript Configuration

For the best experience, ensure your tsconfig.json includes:

{
  "compilerOptions": {
    "strict": true,
    "target": "ES2022",
    "module": "NodeNext",
    "moduleResolution": "NodeNext",
    "esModuleInterop": true,
    "skipLibCheck": true
  }
}

Key settings:

• strict: true - Enables full type checking (required for Effect)
• target: ES2022 - Enables modern JavaScript features used by Effect
• moduleResolution: NodeNext - Proper ESM resolution

Optional: Decorators

If you want to use the decorator-based API (experimental), add:

{
  "compilerOptions": {
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true
  }
}

Verify Installation

Create a simple test file to verify everything is working:

test-install.ts

import { Effect } from "effect"
import * as S from "effect/Schema"
import { GraphQLSchemaBuilder } from "@effect-gql/core"

const schema = GraphQLSchemaBuilder.empty
  .query("hello", {
    type: S.String,
    resolve: () => Effect.succeed("world"),
  })
  .buildSchema()

console.log("Schema created successfully!")
console.log("Query type:", schema.getQueryType()?.name)

Run it:

npx tsx test-install.ts

You should see:

Schema created successfully!
Query type: Query

Next Steps

Now that you have Effect GraphQL installed, continue to the Quick Start guide to build your first API.