Use CheckIfPhoneNumberIsOptedOut with an Amazon SDK or command line tool

    using System;
    using System.Threading.Tasks;
    using Amazon.SimpleNotificationService;
    using Amazon.SimpleNotificationService.Model;

    /// <summary>
    /// This example shows how to use the Amazon Simple Notification Service
    /// (Amazon SNS) to check whether a phone number has been opted out.
    /// </summary>
    public class IsPhoneNumOptedOut
    {
        public static async Task Main()
        {
            string phoneNumber = "+15551112222";

            IAmazonSimpleNotificationService client = new AmazonSimpleNotificationServiceClient();

            await CheckIfOptedOutAsync(client, phoneNumber);
        }

        /// <summary>
        /// Checks to see if the supplied phone number has been opted out.
        /// </summary>
        /// <param name="client">The initialized Amazon SNS Client object used
        /// to check if the phone number has been opted out.</param>
        /// <param name="phoneNumber">A string representing the phone number
        /// to check.</param>
        public static async Task CheckIfOptedOutAsync(IAmazonSimpleNotificationService client, string phoneNumber)
        {
            var request = new CheckIfPhoneNumberIsOptedOutRequest
            {
                PhoneNumber = phoneNumber,
            };

            try
            {
                var response = await client.CheckIfPhoneNumberIsOptedOutAsync(request);

                if (response.HttpStatusCode == System.Net.HttpStatusCode.OK)
                {
                    string optOutStatus = response.IsOptedOut ? "opted out" : "not opted out.";
                    Console.WriteLine($"The phone number: {phoneNumber} is {optOutStatus}");
                }
            }
            catch (AuthorizationErrorException ex)
            {
                Console.WriteLine($"{ex.Message}");
            }
        }
    }

To check SMS message opt-out for a phone number

The following check-if-phone-number-is-opted-out example checks whether the specified phone number is opted out of receiving SMS messages from the current Amazon account.

aws sns check-if-phone-number-is-opted-out \
    --phone-number +1555550100

Output:

{
    "isOptedOut": false
}

import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.sns.SnsClient;
import software.amazon.awssdk.services.sns.model.CheckIfPhoneNumberIsOptedOutRequest;
import software.amazon.awssdk.services.sns.model.CheckIfPhoneNumberIsOptedOutResponse;
import software.amazon.awssdk.services.sns.model.SnsException;

/**
 * Before running this Java V2 code example, set up your development
 * environment, including your credentials.
 *
 * For more information, see the following documentation topic:
 *
 * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
 */
public class CheckOptOut {
    public static void main(String[] args) {

        final String usage = """

                Usage:    <phoneNumber>

                Where:
                   phoneNumber - The mobile phone number to look up (for example, +1XXX5550100).

                """;

        if (args.length != 1) {
            System.out.println(usage);
            System.exit(1);
        }

        String phoneNumber = args[0];
        SnsClient snsClient = SnsClient.builder()
                .region(Region.US_EAST_1)
                .build();

        checkPhone(snsClient, phoneNumber);
        snsClient.close();
    }

    public static void checkPhone(SnsClient snsClient, String phoneNumber) {
        try {
            CheckIfPhoneNumberIsOptedOutRequest request = CheckIfPhoneNumberIsOptedOutRequest.builder()
                    .phoneNumber(phoneNumber)
                    .build();

            CheckIfPhoneNumberIsOptedOutResponse result = snsClient.checkIfPhoneNumberIsOptedOut(request);
            System.out.println(
                    result.isOptedOut() + "Phone Number " + phoneNumber + " has Opted Out of receiving sns messages." +
                            "\n\nStatus was " + result.sdkHttpResponse().statusCode());

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

import { snsClient } from "../libs/snsClient.js";

export const checkIfPhoneNumberIsOptedOut = async (
  phoneNumber = "5555555555",
) => {
  const command = new CheckIfPhoneNumberIsOptedOutCommand({
    phoneNumber,
  });

  const response = await snsClient.send(command);
  console.log(response);
  // {
  //   '$metadata': {
  //     httpStatusCode: 200,
  //     requestId: '3341c28a-cdc8-5b39-a3ee-9fb0ee125732',
  //     extendedRequestId: undefined,
  //     cfId: undefined,
  //     attempts: 1,
  //     totalRetryDelay: 0
  //   },
  //   isOptedOut: false
  // }
  return response;
};

require 'vendor/autoload.php';

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


/**
 * Indicates whether the phone number owner has opted out of receiving SMS messages from your AWS SNS account.
 *
 * 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'
]);

$phone = '+1XXX5550100';

try {
    $result = $SnSclient->checkIfPhoneNumberIsOptedOut([
        'phoneNumber' => $phone,
    ]);
    var_dump($result);
} catch (AwsException $e) {
    // output error message if fails
    error_log($e->getMessage());
}