Get started with Apollo Client

Hello! 👋 This short tutorial gets you up and running with Apollo Client.

For an introduction to the entire Apollo platform, check out Odyssey, Apollo's interactive learning platform.

Step 1: Setup

To start this tutorial, do one of the following:

• Create a new React project locally with Vite, or

• Create a new React sandbox on CodeSandbox.

Step 2: Install dependencies

Applications that use Apollo Client require the following top-level dependencies:

• @apollo/client: This single package contains virtually everything you need to set up Apollo Client. It includes the in-memory cache, local state management, error handling, and a React-based view layer.

• graphql: This package provides logic for parsing GraphQL queries.

• rxjs: This package provides the Observable primitive used throughout Apollo Client.

Run the following command to install both of these packages:

1npm install @apollo/client graphql rxjs

Our example application will use the FlyBy GraphQL API from Apollo Odyssey's Voyage tutorial series. This API provides a list of intergalactic travel locations and details about those locations 👽

Step 3: Initialize ApolloClient

With our dependencies set up, we can now initialize an ApolloClient instance.

In main.jsx, let's first import the symbols we need from @apollo/client and @apollo/client/react:

1import { ApolloClient, HttpLink, InMemoryCache, gql } from "@apollo/client";
2import { ApolloProvider } from "@apollo/client/react";

Next we'll initialize ApolloClient, passing its constructor a configuration object with the link and cache fields:

1const client = new ApolloClient({
2  link: new HttpLink({ uri: "https://flyby-router-demo.herokuapp.com/" }),
3  cache: new InMemoryCache(),
4});

• link specifies the Apollo Link that will be used to execute GraphQL operations against the network. We give it an instance of HttpLink - a customized Apollo Link that knows how to execute network requests against a GraphQL server.

• cache is an instance of InMemoryCache, which Apollo Client uses to cache query results after fetching them.

That's it! Our client is ready to start fetching data. Now before we start using Apollo Client with React, let's first try sending a query with plain JavaScript.

In the same main.jsx file, call client.query() with the query string (wrapped in the gql template literal) shown below:

1// const client = ...
2
3client
4  .query({
5    query: gql`
6      query GetLocations {
7        locations {
8          id
9          name
10          description
11          photo
12        }
13      }
14    `,
15  })
16  .then((result) => console.log(result));

Run this code, open your console, and inspect the result object. You should see a data property with locations attached. Nice!

Although executing GraphQL operations directly like this can be useful, Apollo Client really shines when it's integrated with a view layer like React. You can bind queries to your UI and update it automatically as new data is fetched.

Let's look at how that works!

Step 4: Connect your client to React

You connect Apollo Client to React with the ApolloProvider component. Similar to React's Context.Provider, ApolloProvider wraps your React app and places Apollo Client on the context, enabling you to access it from anywhere in your component tree.

In main.jsx, let's wrap our React app with an ApolloProvider. We suggest putting the ApolloProvider near the root of your application, above any component that might need to access GraphQL data.

1import React from "react";
2import * as ReactDOM from "react-dom/client";
3import { ApolloClient, InMemoryCache } from "@apollo/client";
4import { ApolloProvider } from "@apollo/client/react";
5import App from "./App";
6
7const client = new ApolloClient({
8  uri: "https://flyby-router-demo.herokuapp.com/",
9  cache: new InMemoryCache(),
10});
11
12// Supported in React 18+
13const root = ReactDOM.createRoot(document.getElementById("root"));
14
15root.render(
16  <ApolloProvider client={client}>
17    <App />
18  </ApolloProvider>
19);

Step 5: Fetch data with useQuery

After your ApolloProvider is hooked up, you can start requesting data with useQuery. The useQuery hook is a React hook that shares GraphQL data with your UI.

Switching over to our App.jsx file, we'll start by replacing our existing file contents with the code snippet below:

1// Import everything needed to use the `useQuery` hook
2import { gql } from "@apollo/client";
3import { useQuery } from "@apollo/client/react";
4
5export default function App() {
6  return (
7    <div>
8      <h2>My first Apollo app 🚀</h2>
9    </div>
10  );
11}

We can define the query we want to execute by wrapping it in the gql template literal:

1const GET_LOCATIONS = gql`
2  query GetLocations {
3    locations {
4      id
5      name
6      description
7      photo
8    }
9  }
10`;

Next, let's define a component named DisplayLocations that executes our GET_LOCATIONS query with the useQuery hook:

1function DisplayLocations() {
2  const { loading, error, data } = useQuery(GET_LOCATIONS);
3
4  if (loading) return <p>Loading...</p>;
5  if (error) return <p>Error : {error.message}</p>;
6
7  return data.locations.map(({ id, name, description, photo }) => (
8    <div key={id}>
9      <h3>{name}</h3>
10      <img width="400" height="250" alt="location-reference" src={`${photo}`} />
11      <br />
12      <b>About this location:</b>
13      <p>{description}</p>
14      <br />
15    </div>
16  ));
17}

Whenever this component renders, the useQuery hook automatically executes our query and returns a result object containing loading, error, data, and dataState properties:

• Apollo Client automatically tracks a query's loading and error states, which are reflected in the loading and error properties.

• When the result of your query comes back, it's attached to the data property.

Finally, we'll add DisplayLocations to our existing component tree:

1export default function App() {
2  return (
3    <div>
4      <h2>My first Apollo app 🚀</h2>
5      <br />
6      <DisplayLocations />
7    </div>
8  );
9}

When your app reloads, you should briefly see a loading indicator, followed by a list of locations and details about those locations! If you don't, you can compare your code against the completed app on CodeSandbox.

Congrats, you just made your first component that renders with GraphQL data from Apollo Client! 🎉 Now you can try building more components that use useQuery and experiment with the concepts you just learned.

Next steps

Now that you've learned how to fetch data with Apollo Client, you're ready to dive deeper into creating more complex queries and mutations. After this section, we recommend moving on to:

• Queries: Learn how to fetch queries with arguments and dive deeper into configuration options. For a full list of options, check out the API reference for useQuery.

• Fragments: Learn how to use fragments and data masking to build robust, data-driven components.

• Mutations: Learn how to update data with mutations and when you'll need to update the Apollo cache. For a full list of options, check out the API reference for useMutation.

• Apollo Client API: Sometimes, you'll need to access the client directly like we did in our plain JavaScript example above. Visit the API reference for a full list of options.