i18n-email

Overview

i18n-email supports the Vercel AI SDK as an optional translation backend. Pass any LanguageModel as model in createI18nEmail — no openaiApiKey needed.

Install

Install the ai package and your provider:

npm install ai

Other providers: @ai-sdk/openai, @ai-sdk/anthropic, @ai-sdk/mistral, etc.

Usage

Create a model with your provider function and pass it as model:

import { createI18nEmail } from "i18n-email";
import { createGoogleGenerativeAI } from "@ai-sdk/google";

const google = createGoogleGenerativeAI({
  apiKey: process.env.GEMINI_API_KEY!,
});

const i18nEmail = createI18nEmail({ model: google("gemini-2.5-flash") });

const { subject, html } = await i18nEmail.translate({
  locale: "pl",
  subject: "Welcome!",
  react: <WelcomeEmail name="Dan" />,
});

Providers

Any Vercel AI SDK LanguageModel is supported. Here are some examples:

Google

import { createGoogleGenerativeAI } from "@ai-sdk/google";

const google = createGoogleGenerativeAI({
  apiKey: process.env.GEMINI_API_KEY!,
});

const i18nEmail = createI18nEmail({ model: google("gemini-2.5-flash") });

OpenAI

import { openai } from "@ai-sdk/openai";

const i18nEmail = createI18nEmail({ model: openai("gpt-4o") });

Anthropic

import { anthropic } from "@ai-sdk/anthropic";

const i18nEmail = createI18nEmail({ model: anthropic("claude-4-sonnet") });

Full example with caching and Resend

import { createI18nEmail } from "i18n-email";
import { Redis } from "@upstash/redis";
import { Resend } from "resend";
import { createGoogleGenerativeAI } from "@ai-sdk/google";

const resend = new Resend(process.env.RESEND_API_KEY);
const redis = Redis.fromEnv();

const google = createGoogleGenerativeAI({
  apiKey: process.env.GEMINI_API_KEY!,
});

const i18nEmail = createI18nEmail({
  model: google("gemini-2.5-flash"),
  onTranslate: (info) => {
    console.log(info);
  },
});

const result = await i18nEmail.translate({
  locale: "pl",
  subject: "Welcome!",
  react: (
    <div>
      <h1>Welcome to Our Platform!</h1>
      <p>Your account has been successfully created.</p>
    </div>
  ),
});

await resend.emails.send({
  from: process.env.RESEND_FROM!,
  to: process.env.RESEND_TO!,
  ...result,
});

When model is a Vercel AI SDK model object (detected by specificationVersion, modelId, and provider fields), i18n-email dynamically imports generateObject from ai and calls it with a JSON schema for structured output. If ai is not installed, a descriptive error is thrown at runtime.

Vercel AI SDK