Translate Text Quickstart

Send your first text translation request to the DeepL API and batch multiple strings into a single call.

In this tutorial, you’ll translate your first text with the DeepL API, then batch several strings into a single request. By the end, you’ll have made the two most common types of text translation request, using curl or the official client library for your language.

Prerequisites

• A DeepL API account. Visit our plans page, choose a plan, and sign up. If you already have a DeepL Translator account, you need to log out and create a separate account for the API.
• Your API key, which you can find in your account settings. To learn more about keys, see Authentication.
• curl, or one of the official client libraries for Python, JavaScript, PHP, C#, Java, or Ruby.

If you’re on a free API plan, replace https://api.deepl.com with https://api-free.deepl.com in curl examples. Client libraries detect your account type and pick the correct URL automatically.

Building with an AI coding agent?

Wire it up to the DeepL Docs MCP Server so it can search and read this documentation while it writes code. In Claude Code:

claude mcp add --transport http deepl-docs https://developers.deepl.com/mcp

Then describe what you want to build. To get the same result as this tutorial, paste:

Using the DeepL API, write a script that translates a list of English strings to German and prints the results.

Setup instructions for Claude Desktop, Cursor, VS Code, and other MCP clients are on the Docs MCP Server page.

Step 1: Send your first translation request

A translation request needs only two parameters: text, the text to translate, and target_lang, the language you’re translating to. You don’t need to specify the source language. DeepL detects it and returns it in the response as detected_source_language. If your text is very short or mixes languages, you can pin the source with the optional source_lang parameter.

Language codes follow ISO 639, like DE for German or JA for Japanese, and are case-insensitive. Some target languages support regional variants, like en-US or pt-BR. See the full list of supported languages.

cURL

Set the API key

export API_KEY={YOUR_API_KEY}

Sample request

curl -X POST https://api.deepl.com/v2/translate \
  --header "Content-Type: application/json" \
  --header "Authorization: DeepL-Auth-Key $API_KEY" \
  --data '{
    "text": ["Your order has shipped and will arrive on Tuesday."],
    "target_lang": "DE"
}'

Sample response

{
  "translations": [
    {
      "detected_source_language": "EN",
      "text": "Ihre Bestellung wurde versandt und kommt am Dienstag an."
    }
  ]
}

Python

Install client library

pip install deepl

Sample request

import deepl

auth_key = "{YOUR_API_KEY}"  # replace with your key
deepl_client = deepl.DeepLClient(auth_key)

result = deepl_client.translate_text(
    "Your order has shipped and will arrive on Tuesday.",
    target_lang="DE",
)
print(result.text)

Sample output

Ihre Bestellung wurde versandt und kommt am Dienstag an.

JavaScript

Install client library

npm install deepl-node

Sample request

import * as deepl from 'deepl-node';

const authKey = "{YOUR_API_KEY}"; // replace with your key
const deeplClient = new deepl.DeepLClient(authKey);

(async () => {
    const result = await deeplClient.translateText(
        'Your order has shipped and will arrive on Tuesday.',
        null,
        'de'
    );
    console.log(result.text);
})();

Sample output

Ihre Bestellung wurde versandt und kommt am Dienstag an.

PHP

Install client library

composer require deeplcom/deepl-php

Sample request

require_once 'vendor/autoload.php';
use DeepL\Client;

$authKey = "{YOUR_API_KEY}"; // replace with your key
$deeplClient = new DeepL\DeepLClient($authKey);

$result = $deeplClient->translateText(
    'Your order has shipped and will arrive on Tuesday.',
    null,
    'de'
);
echo $result->text;

Sample output

Ihre Bestellung wurde versandt und kommt am Dienstag an.

C#

Install client library

dotnet add package DeepL.net

Sample request

using DeepL; // this imports the DeepL namespace. Use the code below in your main program.

var authKey = "{YOUR_API_KEY}"; // replace with your key
var client = new DeepLClient(authKey);

var translatedText = await client.TranslateTextAsync(
    "Your order has shipped and will arrive on Tuesday.",
    null,
    LanguageCode.German);
Console.WriteLine(translatedText);

Sample output

Ihre Bestellung wurde versandt und kommt am Dienstag an.

Java

Install client library

// For instructions on installing the DeepL Java library,
// see https://github.com/DeepLcom/deepl-java?tab=readme-ov-file#installation

Sample request

import com.deepl.api.*;

public class Main {
    public static void main(String[] args) throws DeepLException, InterruptedException {
        String authKey = "{YOUR_API_KEY}"; // replace with your key
        DeepLClient client = new DeepLClient(authKey);

        TextResult result = client.translateText(
            "Your order has shipped and will arrive on Tuesday.", null, "de");
        System.out.println(result.getText());
    }
}

Sample output

Ihre Bestellung wurde versandt und kommt am Dienstag an.

Ruby

Install client library

gem install deepl-rb

Sample request

require 'deepl'

DeepL.configure do |config|
    config.auth_key = '{YOUR_API_KEY}' # replace with your key
end

translation = DeepL.translate 'Your order has shipped and will arrive on Tuesday.', nil, 'DE'
puts translation.text

Sample output

Ihre Bestellung wurde versandt und kommt am Dienstag an.

The examples hardcode the key to keep them short. In production code, store your API key in an environment variable instead.

For security reasons, you can’t call the DeepL API directly from client-side JavaScript. During testing or prototyping, route requests through a simple proxy instead.

Step 2: Translate multiple strings in one call

The text parameter is an array, so one request can carry many strings, like every notification in a template file. Each string is translated separately and the response preserves their order. If you don’t set source_lang, DeepL detects the language of each string individually.

Sample request

curl -X POST https://api.deepl.com/v2/translate \
  --header "Content-Type: application/json" \
  --header "Authorization: DeepL-Auth-Key $API_KEY" \
  --data '{
    "text": [
      "Your order has shipped.",
      "Estimated delivery: Tuesday, July 14."
    ],
    "target_lang": "DE"
}'

Sample response

{
  "translations": [
    {
      "detected_source_language": "EN",
      "text": "Ihre Bestellung wurde versandt."
    },
    {
      "detected_source_language": "EN",
      "text": "Voraussichtliche Lieferung: Dienstag, 14. Juli."
    }
  ]
}

The client libraries accept a list of strings in the same translate_text methods you used in step 1.

The total request body is limited to 128 KiB. For anything larger, or for files whose formatting should be preserved, translate a document instead.

Next steps

You’ve now covered the core text translation workflow: single strings and batches. To keep going:

• Translate entire files, formatting included, with the Translate Documents Quickstart
• Try requests with more parameters in our playground or Postman
• Improve translation quality for short or ambiguous text with the context parameter
• Choose between speed- and quality-optimized models with the model_type parameter, documented in the /translate reference
• Translate into regional variants like pt-BR with the language variants guide
• Enforce your terminology with glossaries
• Check usage and limits before going to production