Best Translation API
for JavaScript & Node.js

Here is how you translate text with each SDK in Node.js. The differences in setup complexity and code style are immediately visible:

Google Translate (@google-cloud/translate):

const { Translate } = require("@google-cloud/translate").v2;

// Requires GOOGLE_APPLICATION_CREDENTIALS env var
// pointing to a service account JSON file
const translate = new Translate({ projectId: "my-project" });

async function translateText() {
  const [translation] = await translate.translate(
    "Hello world",
    "nl"
  );
  console.log(translation);
}
translateText();

DeepL (deepl-node):

const deepl = require("deepl-node");

const translator = new deepl.Translator("your-api-key");

async function translateText() {
  const result = await translator.translateText(
    "Hello world",
    null,
    "nl"
  );
  console.log(result.text);
}
translateText();

Langbly (langbly):

const { Langbly } = require("langbly");

const client = new Langbly({ apiKey: "your-api-key" });

async function translateText() {
  const result = await client.translate(
    "Hello world",
    { target: "nl" }
  );
  console.log(result.translatedText);
}
translateText();

Google requires a GCP project, service account JSON file, and environment variable configuration before making your first call. DeepL and Langbly both take a simple API key string, and you can be translating text within 2 minutes of signing up.

For TypeScript projects, the developer experience varies significantly between these SDKs. Langbly is written entirely in TypeScript, so types are first-class citizens, not an afterthought. You get full IntelliSense, typed response objects, and typed error classes out of the box.

DeepL also ships built-in TypeScript types. Google includes @types definitions in the package, but the API surface is larger and more complex due to its multi-cloud architecture.

Where Langbly stands out for JavaScript developers is error handling. The SDK includes built-in auto-retry with exponential backoff for rate limit errors (429) and server errors (5xx). It respects Retry-After headers automatically. Typed error classes like RateLimitError and AuthenticationError make it easy to handle specific failure modes without parsing error messages. DeepL and Google require you to implement retry logic yourself.

Whether you are building a Next.js app, an Express API, or a serverless function, translation API costs scale with your user base. Here is how the three providers compare at typical JavaScript project volumes:

At 5M characters per month (common for a SaaS product with internationalization), Google charges $100, DeepL charges $125, and Langbly charges $19. At 100M characters per month, typical for content platforms or e-commerce sites, Google is $2,000, DeepL is $2,500, and Langbly is $199.

Both Langbly and DeepL offer a permanent 500K characters/month free tier, enough for development, staging environments, and small production apps. Google only provides a one-time $300 trial credit. Langbly also offers 20% off with annual billing on all paid plans.

• How to Use a Translation API in JavaScript
• Google Translate API for Developers: A Complete Guide
• Best Translation API for Python
• Try Langbly free. 500K characters/month, no credit card required