GraphQL API with Apollo Server, Express.js, and Database Integration

GraphQL is a modern and powerful query language for APIs that allows clients to request exactly the data they need. When combined with Apollo Server, Express.js, and MongoDB, you build a flexible, performant, and secure backend for modern applications. Integrating Authentication and Role-Based Access Control (RBAC) ensures fine-grained access control, while DataLoader helps avoid the N+1 query problem common in GraphQL.

This guide walks you through setting up a robust GraphQL API using:

Apollo Server for building the GraphQL server, defining GraphQL schemas and resolvers
Express.js as the HTTP server for middleware and server handling
MongoDB for data persistence accessed via Mongoose
GraphQL Shield and JWT for secure access control: RBAC
DataLoader and Redis for batching and caching database queries efficiently
Prometheus and Grafana for API performance monitoring and observability
GraphiQL for API development, introspection, and documentation

Project Setup

Initialize the Project

mkdir graphql-api
cd graphql-api
npm init -y

Install Required Dependencies

Main dependencies:

npm install @apollo/server graphql express cors graphql-tag

Development dependencies:

npm install -D typescript @types/node @types/express @types/cors

Create tsconfig.json

npx tsc --init

Then update the tsconfig.json (minimal config):

{
  "compilerOptions": {
    "target": "ES6",
    "module": "CommonJS",
    "rootDir": "src",
    "outDir": "dist",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true
  }
}

Project Structure

graphql-api/
├── src/
│ ├── index.ts
│ ├── schema.ts
│ ├── typeDefs.ts
│ └── resolvers.ts
├── tsconfig.json
└── package.json

Setup GraphQL Schema and Resolvers

src/typeDefs.ts

import { gql } from "graphql-tag";

export const typeDefs = gql`
  type Query {
    hello: String
  }
`;

src/resolvers.ts

export const resolvers = {
  Query: {
    hello: () => "Hello, GraphQL with TypeScript!",
  },
};

Set Up Apollo Server with Express

src/index.ts

import express from "express";
import { ApolloServer } from "apollo-server-express";
import { typeDefs } from "./schema";
import { resolvers } from "./resolvers";

async function startServer() {
  const app = express();

  const server = new ApolloServer({
    typeDefs,
    resolvers,
  });

  await server.start();
  server.applyMiddleware({ app });

  const PORT = 4000;
  app.listen(PORT, () => {
    console.log(`🚀 Server ready at http://localhost:${PORT}`);
  });
}

startServer();

Add scripts to package.json

"scripts": {
  "start": "node dist/index.js",
  "dev": "nodemon src/index.ts",
  "build": "tsc"
}

Run Your Project

npm run dev

Open http://localhost:4000/graphql and try:

query {
  hello
}