The `.env` file located in the backend/ directory already contains placeholder credentials and configuration values that LocalStack uses to emulate AWS services. The `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` are placeholder credentials, while `S3_BUCKET_NAME` and `S3_ENDPOINT_URL` are configuration settings. No changes are needed as these values are already correctly set for LocalStack.

   > [!TIP]
   >
   > Given that you’re running Mongo in a Docker container and the backend Node app is running natively on your host, ensure that  `MONGODB_URI=mongodb://localhost:27017/todos` is set in your `.env` file.

   ```plaintext
   MONGODB_URI=mongodb://localhost:27017/todos
   AWS_ACCESS_KEY_ID=test
   AWS_SECRET_ACCESS_KEY=test
   S3_BUCKET_NAME=mysamplebucket
   S3_ENDPOINT_URL=http://localhost:4566
   AWS_REGION=us-east-1
   ```

   While the AWS SDK might typically use environment variables starting with `AWS_`, this specific application directly references the following `S3_*` variables in the index.js file (under the `backend/` directory) to configure the S3Client. 

   ```js
   const s3 = new S3Client({
     endpoint: process.env.S3_ENDPOINT_URL, // Use the provided endpoint or fallback to defaults
     credentials: {
       accessKeyId: process.env.AWS_ACCESS_KEY_ID || 'default_access_key', // Default values for development
       secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY || 'default_secret_key',  
     },
   });
   ```

4. Start the backend server:

   ```console
   $ node index.js
   ```

    You will see the message that the backend service has successfully started at port 5000.

## Start the frontend service

To start the frontend service, open a new terminal and follow these steps:

1. Navigate to the `frontend` directory:

   ```console
   $ cd frontend
   ```

2. Install the required dependencies
  
   ```console
   $ npm install
   ```

3. Start the frontend service

   ```console
   $ npm run dev
   ```
   
   By now, you should see the following message:

   ```console
   VITE v5.4.2  ready in 110 ms
   ➜  Local: http://localhost:5173/
   ➜  Network: use --host to expose
   ➜  press h + enter to show help
   ```

   You can now access the app via [http://localhost:5173](http://localhost:5173). Go ahead, and upload an image by choosing an image file and clicking the **Upload** button.