Cognitive Services : Translate Text into multiple languages using Asp.Net Core & C#


In this article, we are going to learn how to translate text into multiple languages using one of the important Cognitive Services API called Microsoft Translate Text API ( One of the API in Language API ). It’s a simple cloud-based machine translation service and obviously we can test through simple Rest API call. Microsoft is using a new standard for high-quality AI-powered machine translations known as Neural Machine Translation (NMT).

Pic source :

You can also refer the following articles on Cognitive Service.


  1. Subscription key ( Azure Portal ).
  2. Visual Studio 2015 or 2017

Translator Text API

First, we need to log into the Azure Portal with our Azure credentials. Then we need to create an Azure Translator Text API in the Azure portal. So please click on the “Create a resource” on the left top menu and search “Translator Text” in the search bar on the right side window or top of Azure Marketplace.

Click on the “create” button to create Translator Text API.

Provision a Translator Text Subscription Key

After clicking the “Create”, It will open another window. There we need to provide the basic information about Translator Text API.

Name : Name of the Translator Text API ( Eg. TranslatorTextApp ).

Subscription : We can select our Azure subscription for Translator Text  API creation.

Location : We can select our location of resource group. The best thing is we can choose a location closest to our customer.

Pricing tier : Select an appropriate pricing tier for our requirement.

Resource group : We can create a new resource group or choose from an existing one.

Now click on the “TranslatorTextApp” in dashboard page and it will redirect to the detailed page of  TranslatorTextApp ( “Overview” ). Here, we can see the “Keys” ( Subscription key details ) menu in the left side panel. Then click on the “Keys” menu and it will open the Subscription Keys details. We can use any of the subscription keys or regenerate the given key for text translation using Microsoft Translator Text API.

Language Request URL

The following request url gets the set of languages currently supported by other operations of the Microsoft Translator Text API.


The version of the API requested by the client and the Value must be 3.0 and also we can include query parameters and request header in the following endPoint used in our application.

Mandatory required parameters in the query string are “api-version” and “to” . The “api-version” value must be “3.0” as per the current documentation. “to” is the language code parameter used for translating the entered text into the desired language.

The mandatory request headers are “authorization header” and “Content-Type”. We can pass our subscription key into the “authorization header” and the simplest way is to pass our Azure secret key to the Translator service using request header “Ocp-Apim-Subscription-Key”.


The following html contains the binding methodology that we have used in our application by using the  latest Tag helpers of ASP.Net Core.


The following ajax call will trigger for each drop-down index change in the language selection using drop-down list.

// Write your JavaScript code.
$(function () {
        .on('change', '#ddlLangCode', function () {
            var languageCode = $(this).val();
            var enterText = $("#enterText").val();
            if (1 <= $("#enterText").val().trim().length && languageCode != "NA") {


                var url = '/Home/Index';
                var dataToSend = { "LanguageCode": languageCode, "Text": enterText };
                dataType: "json",
                        url: url,
                        data: dataToSend,
                        type: 'POST',
                        success: function (response) {
                            //update control on View
                            var result = JSON.parse(response);
                            var translatedText = result[0].translations[0].text;
            else {


The “ITranslateText” contains one signature for translating text content based on the given input. So we have injected this interface in the ASP.NET Core “Startup.cs” class as a “AddTransient”.

using System.Threading.Tasks;

namespace TranslateTextApp.Business_Layer.Interface
    interface ITranslateText
        Task<string> Translate(string uri, string text, string key);

Translator Text API Service

We can add the valid Translator Text API Subscription Key into the following code.

using Newtonsoft.Json;
using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using TranslateTextApp.Business_Layer.Interface;

namespace TranslateTextApp.Business_Layer
    public class TranslateTextService : ITranslateText
        /// Translate the given text in to selected language.
        /// </summary>

        /// <param name="uri">Request uri</param>
        /// <param name="text">The text is given for translation</param>
        /// <param name="key">Subscription key</param>
        /// <returns></returns>
        public async Task<string> Translate(string uri, string text, string key)
            System.Object[] body = new System.Object[] { new { Text = text } };
            var requestBody = JsonConvert.SerializeObject(body);
            using (var client = new HttpClient())
            using (var request = new HttpRequestMessage())
                request.Method = HttpMethod.Post;
                request.RequestUri = new Uri(uri);
                request.Content = new StringContent(requestBody, Encoding.UTF8, "application/json");
                request.Headers.Add("Ocp-Apim-Subscription-Key", key);

                var response = await client.SendAsync(request);
                var responseBody = await response.Content.ReadAsStringAsync();
                dynamic result = JsonConvert.SerializeObject(JsonConvert.DeserializeObject(responseBody), Formatting.Indented);
                return result;

API Response – Based on the given text

The successful json response.

    "detectedLanguage": {
      "language": "en",
      "score": 1.0
    "translations": [
        "text": "सफलता का कोई शार्टकट नहीं होता",
        "to": "hi"



The given text is translated into desired  language listed in a drop-down list using Microsoft Translator API.



See Also

You can download other source codes from MSDN Code, using the link, mentioned below.


From this article we have learned translate a text(typed in english) in to different languages as per the API documentation using one of the important Cognitive Services API ( Translator Text API is a part of Language API ). I hope this article is useful for all Azure Cognitive Services API beginners.

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