AWS Amplify simplifies building full-stack mobile and web applications by integrating powerful cloud services with minimal configuration. React Native, a popular framework for cross-platform mobile development, pairs perfectly with AWS Amplify to enable features like authentication, storage, and APIs. This article provides a practical example of using AWS Amplify with React Native to build a fully functional app.

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What Is AWS Amplify?

AWS Amplify is a set of tools and services that allows developers to:

• Add features like authentication, APIs, storage, and hosting.
• Automate backend management with minimal coding.
• Integrate seamlessly with popular front-end frameworks, including React Native.

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AWS Amplify React Native Example

Objective

We’ll build a React Native app that:

1. Uses AWS Amplify for authentication.
2. Connects to a GraphQL API to manage a "Todo" list.
3. Stores and retrieves data securely in the cloud.

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Step 1: Set Up Your Environment

Prerequisites

1. Node.js: Install Node.js.
2. React Native CLI: Follow the React Native setup instructions.
3. AWS CLI: Install and configure the AWS CLI.

Create a React Native Project

npx react-native init AmplifyTodoApp
cd AmplifyTodoApp

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Step 2: Install AWS Amplify

Install Amplify Libraries

npm install aws-amplify aws-amplify-react-native

Initialize Amplify

• Choose defaults for most prompts.
• Select React Native as the framework.
• Select default authentication and security configuration.

Push the changes to AWS:

amplify push

Add authentication to the project:

amplify add auth

Configure Amplify in your project:

amplify init

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Step 3: Configure the React Native App

Add Amplify Configuration

Update App.js to configure Amplify:

import React from 'react';
import { Amplify } from 'aws-amplify';
import awsconfig from './src/aws-exports';
import { withAuthenticator } from 'aws-amplify-react-native';

Amplify.configure(awsconfig);

const App = () => {
  return (
    <>
      <YourApp />
    </>
  );
};

export default withAuthenticator(App);

• withAuthenticator: Wraps your app with a prebuilt authentication UI.

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Step 4: Add GraphQL API

• Choose GraphQL as the API type.

Push the API to AWS:

amplify push

Define the schema:

type Todo @model {
  id: ID!
  name: String!
  description: String
}

Add a GraphQL API to your Amplify project:

amplify add api

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Step 5: Fetch and Display Todos

Install Additional Dependencies

npm install @aws-amplify/datastore

Update App.js

import React, { useState, useEffect } from 'react';
import { FlatList, TextInput, Button, Text, View } from 'react-native';
import { DataStore } from '@aws-amplify/datastore';
import { Todo } from './models';

const App = () => {
  const [todos, setTodos] = useState([]);
  const [name, setName] = useState('');
  const [description, setDescription] = useState('');

  useEffect(() => {
    fetchTodos();
  }, []);

  const fetchTodos = async () => {
    const todoList = await DataStore.query(Todo);
    setTodos(todoList);
  };

  const addTodo = async () => {
    await DataStore.save(
      new Todo({
        name,
        description,
      })
    );
    fetchTodos();
  };

  return (
    <View style={{ padding: 20 }}>
      <TextInput
        placeholder="Todo Name"
        value={name}
        onChangeText={setName}
        style={{ borderBottomWidth: 1, marginBottom: 10 }}
      />
      <TextInput
        placeholder="Todo Description"
        value={description}
        onChangeText={setDescription}
        style={{ borderBottomWidth: 1, marginBottom: 10 }}
      />
      <Button title="Add Todo" onPress={addTodo} />
      <FlatList
        data={todos}
        keyExtractor={(item) => item.id}
        renderItem={({ item }) => (
          <View style={{ marginVertical: 10 }}>
            <Text style={{ fontSize: 18 }}>{item.name}</Text>
            <Text>{item.description}</Text>
          </View>
        )}
      />
    </View>
  );
};

export default withAuthenticator(App);

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Step 6: Test the App

1. Sign in using the Amplify-provided authentication UI.
2. Add, view, and manage todos using the app.

Start the app:

npx react-native run-android
# or
npx react-native run-ios

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Best Practices for AWS Amplify with React Native

1. Secure Access: Use Cognito for secure user authentication.
2. Optimize Queries: Use GraphQL queries efficiently to minimize latency.
3. Enable Offline Capabilities: Amplify supports offline data syncing with DataStore.
4. Monitor Usage: Use AWS CloudWatch to monitor API usage and performance.

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Conclusion

AWS Amplify makes it easy to integrate cloud features into your React Native apps. By following this example, you can quickly set up authentication, a GraphQL API, and data management for a fully functional "Todo" app. AWS Amplify's simplicity and scalability make it an excellent choice for building modern mobile applications.