Streamlining API Complexity with GraphQL Gateways

The Problem with Multiple APIs

As organizations grow, so does the complexity of their API architecture. Multiple services emerge, each with its own feature set, and client apps must navigate this intricate landscape. This can lead to development slowdowns, increased errors, and frustrated teams.

When different features have distinct scaling concerns, it’s tempting to create separate services. However, this approach can result in a tangled web of APIs, each with its own protocol, authentication strategy, and data retrieval process. Client apps struggle to interface with these multiple APIs, leading to a costly and risky refactor or rebuild.

Enter API Gateways

API gateways offer a solution to this complexity. By providing a single interface and protocol, they simplify client app development and reduce the burden on backend service teams. GraphQL API gateways take this concept to the next level, leveraging GraphQL’s unique properties to create a unified, scalable, and maintainable architecture.

The Power of GraphQL API Gateways

A GraphQL API gateway can aggregate data from multiple microservices, presenting a single-defined schema to clients. This means clients can query a combination of fields without knowing the underlying data sources. With GraphQL gateways, discovering how to retrieve data becomes a matter of understanding the schema, rather than navigating a complex API landscape.

Schema Stitching: A Key Feature of GraphQL Gateways

To demonstrate the capabilities of GraphQL gateways, let’s explore schema stitching. This approach enables us to create a single GraphQL API that combines data from multiple sources.

type Query {
  launches: [Launch]
  users: [User]
}

type Launch {
  id: ID!
  name: String
  date: Date
}

type User {
  id: ID!
  name: String
  attendedLaunches: [Launch]
}

We can use libraries like GraphQL Mesh to automate this process, saving development time and effort.

A Practical Example: Building a SpaceX Flight Journal API

Using GraphQL Mesh, we can create a simple SpaceX Flight Journal API that records attended launches. Our app will utilize two data sources: a public GraphQL API for SpaceX launch data and a local MongoDB database for user information. GraphQL Mesh will stitch these sources together, generating a unified GraphQL API that allows us to create users, mark attended launches, and query past launches.

const { Mesh } = require('@graphql-mesh/mesh');

const mesh = new Mesh();

mesh.addSchema({
  typeDefs: `
    type Query {
      launches: [Launch]
    }
  `,
  resolvers: {
    Query: {
      launches: async () => {
        // Fetch launches from SpaceX API
      },
    },
  },
});

mesh.addSchema({
  typeDefs: `
    type Query {
      users: [User]
    }
  `,
  resolvers: {
    Query: {
      users: async () => {
        // Fetch users from MongoDB database
      },
    },
  },
});

const stitchedSchema = mesh.stitchSchemas();

// Use the stitched schema to create a unified GraphQL API
const server = new ApolloServer({ typeDefs: stitchedSchema, resolvers: {} });
server.listen().then(({ url }) => {
  console.log(`GraphQL API server listening on ${url}`);
});

The Benefits of GraphQL Gateways

• Simplify client app development
• Reduce the burden on backend service teams
• Improve scalability and maintainability
• Enhance the overall developer experience

By leveraging GraphQL gateways, we can focus on building innovative features, rather than navigating API complexity.