langbly-js

Official JavaScript/TypeScript SDK for the Langbly translation API — a drop-in replacement for Google Translate v2, powered by LLMs.

5-10x cheaper than Google Translate · Better quality · Switch in one PR

Installation

npm install langbly

Quick Start

import { Langbly } from "langbly";

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

// Translate text
const result = await client.translate("Hello world", { target: "nl" });
console.log(result.text); // "Hallo wereld"

// Batch translate
const results = await client.translate(["Hello", "Goodbye"], { target: "nl" });
results.forEach((r) => console.log(r.text));

// Detect language
const detection = await client.detect("Bonjour le monde");
console.log(detection.language); // "fr"

// List supported languages
const languages = await client.languages({ target: "en" });

Migrate from Google Translate

Already using @google-cloud/translate? Switching takes 2 minutes:

// Before (Google Translate)
import { Translate } from "@google-cloud/translate/build/src/v2";
const client = new Translate();
const [translation] = await client.translate("Hello", "nl");

// After (Langbly) — same concepts, better translations, 5x cheaper
import { Langbly } from "langbly";
const client = new Langbly({ apiKey: "your-key" });
const result = await client.translate("Hello", { target: "nl" });

→ Full migration guide: langbly.com/docs/migrate-google

Features

• Google Translate v2 API compatible — same endpoint format
• Zero dependencies — uses native fetch
• Full TypeScript types — interfaces for all request/response shapes
• Auto-retry — exponential backoff on 429/5xx with Retry-After support
• Typed errors — RateLimitError, AuthenticationError, LangblyError
• Batch translation — translate multiple texts in one request
• Language detection — automatic source language identification
• HTML support — translate HTML while preserving tags

Error Handling

import { Langbly, RateLimitError, AuthenticationError } from "langbly";

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

try {
  const result = await client.translate("Hello", { target: "nl" });
} catch (err) {
  if (err instanceof AuthenticationError) {
    console.error("Invalid API key");
  } else if (err instanceof RateLimitError) {
    console.error(`Rate limited — retry after ${err.retryAfter}s`);
  }
}

API Reference

new Langbly(options)

Create a client instance.

• apiKey (string): Your Langbly API key — get one free
• baseUrl (string, optional): Override API URL (default: https://api.langbly.com)
• timeout (number, optional): Request timeout in ms (default: 30000)
• maxRetries (number, optional): Retries for transient errors (default: 2)

client.translate(text, options)

• text (string | string[]): Text(s) to translate
• options.target (string): Target language code
• options.source (string, optional): Source language code
• options.format ("text" | "html", optional): Input format

client.detect(text)

• text (string): Text to analyze

client.languages(options?)

• options.target (string, optional): Language code for names

Links

• Website
• Documentation
• Compare: Langbly vs Google vs DeepL
• Python SDK

License

MIT