Building Serverless GraphQL API in Node with Express and Netlify

Building an API can seem daunting, but it doesn't have to be. This tutorial shows how to create and deploy a simple, read-only API in under an hour using minimal code and readily available tools. No extensive back-end experience is needed; a basic understanding of JavaScript and npm is sufficient.

This guide demystifies common API concepts like REST and introduces GraphQL and serverless architectures. We'll use readily available tools and explain their purpose along the way. By the end, you'll have a deployed API without server management headaches.

Key Concepts: GraphQL and Serverless

APIs fundamentally involve reading and updating data. REST APIs use URLs to define data access points, requiring multiple requests for complex data retrieval. GraphQL improves efficiency by allowing clients to specify the exact data needed in a single request. Data relationships are represented as a graph, optimizing data fetching.

Serverless architecture eliminates the need for managing servers. You pay only for the resources consumed, simplifying deployment and maintenance. We'll leverage Netlify Functions for this serverless functionality.

Tools of the Trade

1. Node.js and Express: Node.js allows server-side JavaScript execution, while Express simplifies API development with features like routing and middleware.

2. Netlify Functions: A serverless platform providing free deployment and scaling of functions. Netlify Dev allows local testing.

Project Setup

1. Create a new project directory and initialize it with npm init.

2. Install necessary packages: npm i express express-graphql graphql body-parser serverless-http netlify-cli -g

File Structure and Configuration

• netlify.toml: Configures Netlify for building and deploying. Crucially, it specifies the location of serverless functions:

[build]
command = "npm run build"
publish = "build"
functions = "functions"

• /functions/api.js: Contains the API code.

api.js Code Breakdown

1. Import Dependencies:

const express = require("express");
const bodyParser = require("body-parser");
const expressGraphQL = require("express-graphql");
const serverless = require("serverless-http");
const { GraphQLSchema, GraphQLObjectType, GraphQLString } = require("graphql");

2. Initialize Express and Serverless Wrapper:

const app = express();
module.exports.handler = serverless(app);

3. Configure Express Middleware:

app.use(bodyParser.json());
app.use("/", expressGraphQL({ schema: schema, graphiql: true }));

4. Define the GraphQL Schema:

const schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: "HelloWorld",
    fields: () => ({
      message: {
        type: GraphQLString,
        resolve: () => "Hello World",
      },
    }),
  }),
});

Local Development and Testing

Run netlify dev in your terminal. Access the GraphiQL playground at http://localhost:8888/.netlify/functions/api. Test your API by querying { message }.

Deployment

Connect your project to Netlify (e.g., via GitHub) for automatic deployment. Netlify will handle building and deploying your serverless function.

Optional: Request Redirection

Create a _redirects file in your project root to redirect requests from /api to your Netlify function:

<code>/api /.netlify/functions/api 200!</code>

This simplifies API access.

Conclusion

This tutorial provides a foundation for building and deploying serverless GraphQL APIs with ease. The approach is scalable and allows for more complex API development as needed. Remember to explore the linked resources for deeper dives into GraphQL and serverless technologies. The complete source code is available on GitHub (link provided in original article).

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