Quickstart: Get started with Translator

  • 35 minutes to read

In this quickstart, you learn to use the Translator service via REST. You start with basic examples and move onto some core configuration options that are commonly used during development, including:

Prerequisites

  • Azure subscription - Create one for free
  • Once you have an Azure subscription, create a Translator resource in the Azure portal to get your key and endpoint. After it deploys, select Go to resource.
    • You'll need the key and endpoint from the resource to connect your application to the Translator service. You'll paste your key and endpoint into the code below later in the quickstart.
    • You can use the free pricing tier (F0) to try the service, and upgrade later to a paid tier for production.

Platform setup

  • Create a new project: dotnet new console -o your_project_name
  • Replace Program.cs with the C# code shown below.
  • Set the subscription key and endpoint values in Program.cs.
  • Add Newtonsoft.Json using .NET CLI.
  • Run the program from the project directory: dotnet run

Headers

When calling the Translator service via REST, you'll need to make sure the following headers are included with each request. Don't worry, we'll include the headers in the sample code in the following sections.

Headers Description
Authentication header(s) Required request header.
See available options for authentication.
Content-Type Required request header.
Specifies the content type of the payload.
Accepted value is application/json; charset=UTF-8.
Content-Length Required request header.
The length of the request body.
X-ClientTraceId Optional.
A client-generated GUID to uniquely identify the request. You can omit this header if you include the trace ID in the query string using a query parameter named ClientTraceId.

Keys and endpoints

The samples on this page use hard-coded keys and endpoints for simplicity. Remember to remove the key from your code when you're done, and never post it publicly. For production, consider using a secure way of storing and accessing your credentials. See the Cognitive Services security article for more information.

Translate text

The core operation of the Translator service is to translate text. In this section, you'll build a request that takes a single source (from) and provides two outputs (to). Then we'll review some parameters that can be used to adjust both the request and the response.

using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json; // Install Newtonsoft.Json with NuGet

class Program
{
    private static readonly string subscriptionKey = "YOUR-SUBSCRIPTION-KEY";
    private static readonly string endpoint = "https://api.cognitive.microsofttranslator.com/";
    
    static async Task Main(string[] args)
    {
        // Input and output languages are defined as parameters.
        string route = "/translate?api-version=3.0&from=en&to=de&to=it";
        string textToTranslate = "Hello, world!";
        object[] body = new object[] { new { Text = textToTranslate } };
        var requestBody = JsonConvert.SerializeObject(body);
    
        using (var client = new HttpClient())
        using (var request = new HttpRequestMessage())
        {
            // Build the request.
            request.Method = HttpMethod.Post;
            request.RequestUri = new Uri(endpoint + route);
            request.Content = new StringContent(requestBody, Encoding.UTF8, "application/json");
            request.Headers.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
    
            // Send the request and get response.
            HttpResponseMessage response = await client.SendAsync(request).ConfigureAwait(false);
            // Read response as a string.
            string result = await response.Content.ReadAsStringAsync();
            Console.WriteLine(result);
        }
    }
}

After a successful call, you should see the following response:

[
    {
        "translations": [
            {
                "text": "Hallo Welt!",
                "to": "de"
            },
            {
                "text": "Salve, mondo!",
                "to": "it"
            }
        ]
    }
]

Detect language

If you know that you'll need translation, but don't know the language of the text that will be sent to the Translator service, you can use the language detection operation. There's more than one way to identify the source text language. In this section, you'll learn how to use language detection using the translate endpoint, and the detect endpoint.

Detect source language during translation

If you don't include the from parameter in your translation request, the Translator service will attempt to detect the source text's language. In the response, you'll get the detected language (language) and a confidence score (score). The closer the score is to 1.0, means that there is increased confidence that the detection is correct.

using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json; // Install Newtonsoft.Json with NuGet

class Program
{
    private static readonly string subscriptionKey = "YOUR-SUBSCRIPTION-KEY";
    private static readonly string endpoint = "https://api.cognitive.microsofttranslator.com/";
    
    static async Task Main(string[] args)
    {
        // Output languages are defined as parameters, input language detected.
        string route = "/translate?api-version=3.0&to=de&to=it";
        string textToTranslate = "Hello, world!";
        object[] body = new object[] { new { Text = textToTranslate } };
        var requestBody = JsonConvert.SerializeObject(body);
    
        using (var client = new HttpClient())
        using (var request = new HttpRequestMessage())
        {
            // Build the request.
            request.Method = HttpMethod.Post;
            request.RequestUri = new Uri(endpoint + route);
            request.Content = new StringContent(requestBody, Encoding.UTF8, "application/json");
            request.Headers.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
    
            // Send the request and get response.
            HttpResponseMessage response = await client.SendAsync(request).ConfigureAwait(false);
            // Read response as a string.
            string result = await response.Content.ReadAsStringAsync();
            Console.WriteLine(result);
        }
    }
}

After a successful call, you should see the following response:

[
    {
        "detectedLanguage": {
            "language": "en",
            "score": 1.0
        },
        "translations": [
            {
                "text": "Hallo Welt!",
                "to": "de"
            },
            {
                "text": "Salve, mondo!",
                "to": "it"
            }
        ]
    }
]

Detect source language without translation

It's possible to use the Translator service to detect the language of source text without performing a translation. To do this, you'll use the /detect endpoint.

using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json; // Install Newtonsoft.Json with NuGet

class Program
{
    private static readonly string subscriptionKey = "YOUR-SUBSCRIPTION-KEY";
    private static readonly string endpoint = "https://api.cognitive.microsofttranslator.com/";
    
    static async Task Main(string[] args)
    {
        // Just detect language
        string route = "/detect?api-version=3.0";
        string textToLangDetect = "Ich würde wirklich gern Ihr Auto um den Block fahren ein paar Mal.";
        object[] body = new object[] { new { Text = textToLangDetect } };
        var requestBody = JsonConvert.SerializeObject(body);
    
        using (var client = new HttpClient())
        using (var request = new HttpRequestMessage())
        {
            // Build the request.
            request.Method = HttpMethod.Post;
            request.RequestUri = new Uri(endpoint + route);
            request.Content = new StringContent(requestBody, Encoding.UTF8, "application/json");
            request.Headers.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
    
            // Send the request and get response.
            HttpResponseMessage response = await client.SendAsync(request).ConfigureAwait(false);
            // Read response as a string.
            string result = await response.Content.ReadAsStringAsync();
            Console.WriteLine(result);
        }
    }
}

When using the /detect endpoint, the response will include alternate detections, and will let you know if translation and transliteration are supported for all of the detected languages. After a successful call, you should see the following response:

[
    {
        "alternatives": [
            {
                "isTranslationSupported": true,
                "isTransliterationSupported": false,
                "language": "nl",
                "score": 0.92
            },
            {
                "isTranslationSupported": true,
                "isTransliterationSupported": false,
                "language": "sk",
                "score": 0.77
            }
        ],
        "isTranslationSupported": true,
        "isTransliterationSupported": false,
        "language": "de",
        "score": 1.0
    }
]

Transliterate text

Transliteration is the process of converting a word or phrase from the script (alphabet) of one language to another based on phonetic similarity. For example, you could use transliteration to convert "สวัสดี" (thai) to "sawatdi" (latn). There's more than one way to perform transliteration. In this section, you'll learn how to use language detection using the translate endpoint, and the transliterate endpoint.

Transliterate during translation

If you're translating into a language that uses a different alphabet (or phonemes) than your source, you might need a transliteration. In this example, we translate "Hello" from English to Thai. In addition to getting the translation in Thai, you'll get a transliteration of the translated phrase using the Latin alphabet.

To get a transliteration from the translate endpoint, use the toScript parameter.

![NOTE] For a complete list of available languages and transliteration options, see language support.

using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json; // Install Newtonsoft.Json with NuGet

class Program
{
    private static readonly string subscriptionKey = "YOUR-SUBSCRIPTION-KEY";
    private static readonly string endpoint = "https://api.cognitive.microsofttranslator.com/";
    
    static async Task Main(string[] args)
    {
        // Output language defined as parameter, with toScript set to latn
        string route = "/translate?api-version=3.0&to=th&toScript=latn";
        string textToTransliterate = "Hello";
        object[] body = new object[] { new { Text = textToTransliterate } };
        var requestBody = JsonConvert.SerializeObject(body);
    
        using (var client = new HttpClient())
        using (var request = new HttpRequestMessage())
        {
            // Build the request.
            request.Method = HttpMethod.Post;
            request.RequestUri = new Uri(endpoint + route);
            request.Content = new StringContent(requestBody, Encoding.UTF8, "application/json");
            request.Headers.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
    
            // Send the request and get response.
            HttpResponseMessage response = await client.SendAsync(request).ConfigureAwait(false);
            // Read response as a string.
            string result = await response.Content.ReadAsStringAsync();
            Console.WriteLine(result);
        }
    }
}

After a successful call, you should see the following response. Keep in mind that the response from translate endpoint includes the detected source language with a confidence score, a translation using the alphabet of the output language, and a transliteration using the Latin alphabet.

[
    {
        "detectedLanguage": {
            "language": "en",
            "score": 1.0
        },
        "translations": [
            {
                "text": "สวัสดี",
                "to": "th",
                "transliteration": {
                    "script": "Latn",
                    "text": "sawatdi"
                }
            }
        ]
    }
]

Transliterate without translation

You can also use the transliterate endpoint to get a transliteration. When using the transliteration endpoint, you must provide the source language (language), the source script/alphabet (fromScript), and the output script/alphabet (toScript) as parameters. In this example, we're going to get the transliteration for สวัสดี.

![NOTE] For a complete list of available languages and transliteration options, see language support.

using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json; // Install Newtonsoft.Json with NuGet

class Program
{
    private static readonly string subscriptionKey = "YOUR-SUBSCRIPTION-KEY";
    private static readonly string endpoint = "https://api.cognitive.microsofttranslator.com/";
    
    static async Task Main(string[] args)
    {
        // For a complete list of options, see API reference.
        // Input and output languages are defined as parameters.
        string route = "/translate?api-version=3.0&to=th&toScript=latn";
        string textToTransliterate = "Hello";
        object[] body = new object[] { new { Text = textToTransliterate } };
        var requestBody = JsonConvert.SerializeObject(body);
    
        using (var client = new HttpClient())
        using (var request = new HttpRequestMessage())
        {
            // Build the request.
            request.Method = HttpMethod.Post;
            request.RequestUri = new Uri(endpoint + route);
            request.Content = new StringContent(requestBody, Encoding.UTF8, "application/json");
            request.Headers.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
    
            // Send the request and get response.
            HttpResponseMessage response = await client.SendAsync(request).ConfigureAwait(false);
            // Read response as a string.
            string result = await response.Content.ReadAsStringAsync();
            Console.WriteLine(result);
        }
    }
}

After a successful call, you should see the following response. Unlike the call to the translate endpoint, transliterate only returns the script and the output text.

[
    {
        "script": "latn",
        "text": "sawatdi"
    }
]

Get sentence length

With the Translator service, you can get the character count for a sentence or series of sentences. The response is returned as an array, with character counts for each sentence detected. You can get sentence lengths with the translate and breaksentence endpoints.

Get sentence length during translation

You can get character counts for both source text and translation output using the translate endpoint. To return sentence length (srcSenLen and transSenLen) you must set the includeSentenceLength parameter to True.

using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json; // Install Newtonsoft.Json with NuGet

class Program
{
    private static readonly string subscriptionKey = "YOUR-SUBSCRIPTION-KEY";
    private static readonly string endpoint = "https://api.cognitive.microsofttranslator.com/";
    
    static async Task Main(string[] args)
    {
        // Include sentence length details.
        string route = "/translate?api-version=3.0&to=es&includeSentenceLength=true";
        string sentencesToCount = 
                "Can you tell me how to get to Penn Station? Oh, you aren't sure? That's fine.";
        object[] body = new object[] { new { Text = sentencesToCount } };
        var requestBody = JsonConvert.SerializeObject(body);
    
        using (var client = new HttpClient())
        using (var request = new HttpRequestMessage())
        {
            // Build the request.
            request.Method = HttpMethod.Post;
            request.RequestUri = new Uri(endpoint + route);
            request.Content = new StringContent(requestBody, Encoding.UTF8, "application/json");
            request.Headers.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
    
            // Send the request and get response.
            HttpResponseMessage response = await client.SendAsync(request).ConfigureAwait(false);
            // Read response as a string.
            string result = await response.Content.ReadAsStringAsync();
            Console.WriteLine(result);
        }
    }
}

After a successful call, you should see the following response. In addition to the detected source language and translation, you'll get character counts for each detected sentence for both the source (srcSentLen) and translation (transSentLen).

[
    {
        "detectedLanguage": {
            "language": "en",
            "score": 1.0
        },
        "translations": [
            {
                "sentLen": {
                    "srcSentLen": [
                        44,
                        21,
                        12
                    ],
                    "transSentLen": [
                        48,
                        18,
                        10
                    ]
                },
                "text": "¿Puedes decirme cómo llegar a la estación Penn? ¿No estás seguro? Está bien.",
                "to": "es"
            }
        ]
    }
]

Get sentence length without translation

The Translator service also lets you request sentence length without translation using the breaksentence endpoint.

using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json; // Install Newtonsoft.Json with NuGet

class Program
{
    private static readonly string subscriptionKey = "YOUR-SUBSCRIPTION-KEY";
    private static readonly string endpoint = "https://api.cognitive.microsofttranslator.com/";
    
    static async Task Main(string[] args)
    {
        // Only include sentence length details.
        string route = "/breaksentence?api-version=3.0";
        string sentencesToCount = 
                "Can you tell me how to get to Penn Station? Oh, you aren't sure? That's fine.";
        object[] body = new object[] { new { Text = sentencesToCount } };
        var requestBody = JsonConvert.SerializeObject(body);
    
        using (var client = new HttpClient())
        using (var request = new HttpRequestMessage())
        {
            // Build the request.
            request.Method = HttpMethod.Post;
            request.RequestUri = new Uri(endpoint + route);
            request.Content = new StringContent(requestBody, Encoding.UTF8, "application/json");
            request.Headers.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
    
            // Send the request and get response.
            HttpResponseMessage response = await client.SendAsync(request).ConfigureAwait(false);
            // Read response as a string.
            string result = await response.Content.ReadAsStringAsync();
            Console.WriteLine(result);
        }
    }
}

After a successful call, you should see the following response. Unlike the call to the translate endpoint, breaksentence only returns the character counts for the source text in an array called sentLen.

[
    {
        "detectedLanguage": {
            "language": "en",
            "score": 1.0
        },
        "sentLen": [
            44,
            21,
            12
        ]
    }
]

Dictionary lookup (alternate translations)

With the endpoint, you can get alternate translations for a word or phrase. For example, when translating the word "shark" from en to es, this endpoint returns both "tiburón" and "escualo".

using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json; // Install Newtonsoft.Json with NuGet

class Program
{
    private static readonly string subscriptionKey = "YOUR-SUBSCRIPTION-KEY";
    private static readonly string endpoint = "https://api.cognitive.microsofttranslator.com/";
    
    static async Task Main(string[] args)
    {
        // See many translation options
        string route = "/dictionary/lookup?api-version=3.0&from=en&to=es";
        string wordToTranslate = "shark";
        object[] body = new object[] { new { Text = wordToTranslate } };
        var requestBody = JsonConvert.SerializeObject(body);
    
        using (var client = new HttpClient())
        using (var request = new HttpRequestMessage())
        {
            // Build the request.
            request.Method = HttpMethod.Post;
            request.RequestUri = new Uri(endpoint + route);
            request.Content = new StringContent(requestBody, Encoding.UTF8, "application/json");
            request.Headers.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
    
            // Send the request and get response.
            HttpResponseMessage response = await client.SendAsync(request).ConfigureAwait(false);
            // Read response as a string.
            string result = await response.Content.ReadAsStringAsync();
            Console.WriteLine(result);
        }
    }
}

After a successful call, you should see the following response. Let's break this down since the JSON is more complex than some of the other examples in this article. The translations array includes a list of translations. Each object in this array includes a confidence score (confidence), the text optimized for end-user display (displayTarget), the normalized text (normalizedText), the part of speech (posTag), and information about previous translation (backTranslations). For more information about the response, see Dictionary Lookup

[
    {
        "displaySource": "shark",
        "normalizedSource": "shark",
        "translations": [
            {
                "backTranslations": [
                    {
                        "displayText": "shark",
                        "frequencyCount": 45,
                        "normalizedText": "shark",
                        "numExamples": 0
                    }
                ],
                "confidence": 0.8182,
                "displayTarget": "tiburón",
                "normalizedTarget": "tiburón",
                "posTag": "OTHER",
                "prefixWord": ""
            },
            {
                "backTranslations": [
                    {
                        "displayText": "shark",
                        "frequencyCount": 10,
                        "normalizedText": "shark",
                        "numExamples": 1
                    }
                ],
                "confidence": 0.1818,
                "displayTarget": "escualo",
                "normalizedTarget": "escualo",
                "posTag": "NOUN",
                "prefixWord": ""
            }
        ]
    }
]

Dictionary examples (translations in context)

After you've performed a dictionary lookup, you can pass the source text and translation to the dictionary/examples endpoint to get a list of examples that show both terms in the context of a sentence or phrase. Building on the previous example, you'll use the normalizedText and normalizedTarget from the dictionary lookup response as text and translation respectively. The source language (from) and output target (to) parameters are required.

using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json; // Install Newtonsoft.Json with NuGet

class Program
{
    private static readonly string subscriptionKey = "YOUR-SUBSCRIPTION-KEY";
    private static readonly string endpoint = "https://api.cognitive.microsofttranslator.com/";
    
    static async Task Main(string[] args)
    {
        // See examples of terms in context
        string route = "/dictionary/examples?api-version=3.0&from=en&to=es";
        object[] body = new object[] { new { Text = "Shark",  Translation = "tiburón" } } ;
        var requestBody = JsonConvert.SerializeObject(body);
    
        using (var client = new HttpClient())
        using (var request = new HttpRequestMessage())
        {
            // Build the request.
            request.Method = HttpMethod.Post;
            request.RequestUri = new Uri(endpoint + route);
            request.Content = new StringContent(requestBody, Encoding.UTF8, "application/json");
            request.Headers.Add("Ocp-Apim-Subscription-Key", subscriptionKey);
    
            // Send the request and get response.
            HttpResponseMessage response = await client.SendAsync(request).ConfigureAwait(false);
            // Read response as a string.
            string result = await response.Content.ReadAsStringAsync();
            Console.WriteLine(result);
        }
    }
}

After a successful call, you should see the following response. For more information about the response, see Dictionary Lookup

[
    {
        "examples": [
            {
                "sourcePrefix": "More than a match for any ",
                "sourceSuffix": ".",
                "sourceTerm": "shark",
                "targetPrefix": "Más que un fósforo para cualquier ",
                "targetSuffix": ".",
                "targetTerm": "tiburón"
            },
            {
                "sourcePrefix": "Same with the mega ",
                "sourceSuffix": ", of course.",
                "sourceTerm": "shark",
                "targetPrefix": "Y con el mega ",
                "targetSuffix": ", por supuesto.",
                "targetTerm": "tiburón"
            },
            {
                "sourcePrefix": "A ",
                "sourceSuffix": " ate it.",
                "sourceTerm": "shark",
                "targetPrefix": "Te la ha comido un ",
                "targetSuffix": ".",
                "targetTerm": "tiburón"
            }
        ],
        "normalizedSource": "shark",
        "normalizedTarget": "tiburón"
    }
]

Next steps

See also