Confirm an endpoint owner wants to receive Amazon SNS messages using an Amazon SDK

    public static void confirmSub(SnsClient snsClient, String subscriptionToken, String topicArn ) {

        try {
            ConfirmSubscriptionRequest request = ConfirmSubscriptionRequest.builder()
                .token(subscriptionToken)
                .topicArn(topicArn)
                .build();

            ConfirmSubscriptionResponse result = snsClient.confirmSubscription(request);
            System.out.println("\n\nStatus was " + result.sdkHttpResponse().statusCode() + "\n\nSubscription Arn: \n\n" + result.subscriptionArn());

        } catch (SnsException e) {
        System.err.println(e.awsErrorDetails().errorMessage());
        System.exit(1);
        }
    }

Create the client in a separate module and export it.

import { SNSClient } from "@aws-sdk/client-sns";

// The AWS Region can be provided here using the `region` property. If you leave it blank
// the SDK will default to the region set in your AWS config.
export const snsClient = new SNSClient({});

Import the SDK and client modules and call the API.

import { ConfirmSubscriptionCommand } from "@aws-sdk/client-sns";
import { snsClient } from "../libs/snsClient.js";

/**
 * @param {string} token - This token is sent the subscriber. Only subscribers
 *                         that are not AWS services (HTTP/S, email) need to be confirmed.
 * @param {string} topicArn - The ARN of the topic for which you wish to confirm a subscription.
 */
export const confirmSubscription = async (
  token = "TOKEN",
  topicArn = "TOPIC_ARN"
) => {
  const response = await snsClient.send(
    // A subscription only needs to be confirmed if the endpoint type is
    // HTTP/S, email, or in another AWS account.
    new ConfirmSubscriptionCommand({
      Token: token,
      TopicArn: topicArn,
      // If this is true, the subscriber cannot unsubscribe while unauthenticated.
      AuthenticateOnUnsubscribe: "false",
    })
  );
  console.log(response);
  // {
  //   '$metadata': {
  //     httpStatusCode: 200,
  //     requestId: '4bb5bce9-805a-5517-8333-e1d2cface90b',
  //     extendedRequestId: undefined,
  //     cfId: undefined,
  //     attempts: 1,
  //     totalRetryDelay: 0
  //   },
  //   SubscriptionArn: 'arn:aws:sns:us-east-1:xxxxxxxxxxxx:TOPIC_NAME:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx'
  // }
  return response;
};

require 'vendor/autoload.php';

use Aws\Sns\SnsClient; 
use Aws\Exception\AwsException;

/**
 * Verifies an endpoint owner's intent to receive messages by validating the token sent to the endpoint by an earlier Subscribe action.
 *
 * This code expects that you have AWS credentials set up per:
 * https://docs.aws.amazon.com/sdk-for-php/v3/developer-guide/guide_credentials.html
 */
 
$SnSclient = new SnsClient([
    'profile' => 'default',
    'region' => 'us-east-1',
    'version' => '2010-03-31'
]);

$subscription_token = 'arn:aws:sns:us-east-1:111122223333:MyTopic:123456-abcd-12ab-1234-12ba3dc1234a';
$topic = 'arn:aws:sns:us-east-1:111122223333:MyTopic';

try {
    $result = $SnSclient->confirmSubscription([
        'Token' => $subscription_token,
        'TopicArn' => $topic,
    ]);
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}