Use Amplify Storage with any S3 bucket

With Amplify Storage APIs, you can use your own S3 buckets instead of the Amplify-created ones.

Use storage resources with an Amplify backend

Add necessary permissions to the S3 bucket

For the specific Amazon S3 bucket that you want to use with these APIs, you need to make sure that the associated IAM role has the necessary permissions to read and write data to that bucket.

To do this, go to Amazon S3 console > Select the S3 bucket > Permissions > Edit Bucket Policy.

The policy will look something like this

{
	"Version": "2012-10-17",
	"Statement": [
		{
			"Sid": "Statement1",
			"Principal": { "AWS": "arn:aws:iam::<AWS-account-ID>:role/<role-name>" },
			"Effect": "Allow",
			"Action": [
				"s3:PutObject",
				"s3:GetObject",
				"s3:DeleteObject",
				"s3:ListBucket"
			],
			"Resource": [
				"arn:aws:s3:::<bucket-name>/*"
			]
		}
	]
}

Replace <AWS-account-ID> with your AWS account ID and <role-name> with the IAM role associated with your Amplify Auth setup. Replace <bucket-name> with the S3 bucket name.

You can refer to Amazon S3's Policies and Permissions documentation for more ways to customize access to the bucket.

Specify S3 bucket in Amplify's backend config

Next, use the addOutput method from the backend definition object to define a custom s3 bucket by specifying the name and region of the bucket in your amplify/backend.ts file.

import { defineBackend } from '@aws-amplify/backend';
import { auth } from './auth/resource';
import { data } from './data/resource';

const backend = defineBackend({
  auth,
  data,
});

Copy highlighted code example
backend.addOutput({
  storage: {
    aws_region: "<region>",
    bucket_name: "<bucket-name>"
  },
});

Import latest amplify_outputs.dart file

To ensure the local amplify_outputs.dart file is up-to-date, you can run the npx ampx generate outputs command.

Now that you've configured the necessary permissions, you can start using the storage APIs with your chosen S3 bucket.