Sinch Java SDK for Voice

The Sinch Voice Java SDK allows you to quickly interact with the Voice API from inside your Java applications. The fastest way to get started with the SDK is to check out our getting started guides. There you'll find all the instructions necessary to download, install, set up, and start using the SDK.

Syntax

When using the Java SDK, the code representing requests and queries sent to and responses received from the Voice API are structured similarly to those that are sent and received using the Voice API itself.

The code sample on the side of this page is an example of how to use the Java SDK to make a text to speech phone call to phone number using the Java SDK and the Voice API. The code is also displayed below, along with a REST API call that accomplishes the same task, for reference:

package app;

import java.net.*;
import java.net.http.*;
import java.util.*;

public class App {
  private static final String key = "";
  private static final String secret = "";
  private static final String fromNumber = "";
  private static final String to = "";
  private static final String locale = "";

  public static void main(String[] args) throws Exception {
    var httpClient = HttpClient.newBuilder().build();

    var payload = String.join("\n"
      , "{"
      , " \"method\": \"ttsCallout\","
      , " \"ttsCallout\": {"
      , "  \"cli\": \"" + fromNumber + "\","
      , "  \"destination\": {"
      , "   \"type\": \"number\","
      , "   \"endpoint\": \"" + to + "\""
      , "  },"
      , "  \"locale\": \"" + locale + "\","
      , "  \"text\": \"Hello, this is a call from Sinch. Congratulations! You made your first call.\""
      , " }"
      , "}"
    );

    var host = "https://calling.api.sinch.com";
    var pathname = "/calling/v1/callouts";
    var request = HttpRequest.newBuilder()
      .POST(HttpRequest.BodyPublishers.ofString(payload))
      .uri(URI.create(host + pathname ))
      .header("Content-Type", "application/json")
      .header("Authorization", "Basic " + Base64.getEncoder().encodeToString((key + ":" + secret).getBytes()))
      .build();

    var response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());

    System.out.println(response.body());
  }
}

package voice;

import com.sinch.sdk.domains.voice.api.v1.*;
import com.sinch.sdk.domains.voice.models.v1.*;
import com.sinch.sdk.domains.voice.models.requests.*;

public class Snippet {

  public static String execute(VoiceService voiceService) {

    CalloutsService calloutsService = voiceService.callouts();

    String phoneNumber = "YOUR_phone_number";
    String message = "Hello, this is a call from Sinch. Congratulations! You made your first call.";

    CalloutRequestTTS parameters =
        CalloutRequestTTS.builder()
            .setDestination(DestinationPstn.from(phoneNumber))
            .setText(message)
            .build();

    String callId = calloutsService.textToSpeech(parameters);
    return callId;
  }
}

This example highlights the following required to successfully make a Voice API call using the Sinch Java SDK:

• Client initialization
• Voice domain
• Endpoint usage
• Field population

Client

When using the Sinch Java SDK, you initialize communication with the Sinch backend by initializing the Java SDK's main client class. This client allows you to access the functionality of the Sinch Java SDK.

Initialization

To start using the SDK, you need to initialize the main client class and create a configuration object to connect to your Sinch account and Voice app. You can find all of the credentials you need on your Sinch dashboard.

import com.sinch.sdk.SinchClient;
import com.sinch.sdk.models.Configuration;

public class App {
    
    public static void main(String[] args) {
        SinchClient client = new SinchClient(Configuration.builder()
                                    .setApplicationKey("YOUR_application_key")
                                    .setApplicationSecret("YOUR_application_secret")
                                    .build());
    }
}

Voice domain

Endpoint categories

In the Sinch Java SDK, Voice API endpoints are accessible through the client. The naming convention of the endpoint's representation in the SDK matches the API:

• voice().v1().callouts()
• voice().v1().calls()
• voice().v1().conferences()
• voice().v1().applications()

For example:

var response = client.voice()
                    .v1()
                    .callouts()
                    .textToSpeech(CalloutRequestTTS
                                .builder()
                                .setDestination(DestinationPstn.from(phoneNumber))
                                .setText("Thank you for calling Sinch. This call will now end.")
                                .build());

voice().v1().callouts() endpoint category

voice().v1().calls() endpoint category

voice().v1().conferences() endpoint category

voice().v1().applications() endpoint category

voice().v1().webhooks() endpoint category

Request and query parameters

Requests and queries made using the Java SDK are similar to those made using the Voice API. Many of the fields are named and structured similarly.

Many fields in the Java SDK are rendered as enums in data models.

Nested objects

When making calls directly to the API, we use JSON objects, including (in some cases) nested JSON objects. When using the Java SDK, we use Java data models instead of nested JSON objects. For example, consider the Voice configuration objects below. One is represented in JSON, the other as a Java object:

CalloutRequestTTS.builder()
            .setDestination(DestinationPstn.from(phoneNumber))
            .setText("Thank you for calling Sinch. This call will now end.")
            .build()

{
  "method": "ttsCallout",
  "ttsCallout": {
    "destination": {
      "type": "number",
      "endpoint": "YOUR_phone_number"
    },
    "text": "Thank you for calling Sinch. This call will now end."
  }
}

Responses

Response fields match the API responses. They are delivered as Java objects.