Basic dev email client

create-email-client.ts

import { createDevEmailClient } from '@/lib/email/dev-email-client'
import { createProductionEmailClient } from '@/lib/email/production-email-client'

export function createEmailClient(environment: 'development' | 'production') {
  if (environment === 'development') {
    return createDevEmailClient()
  }
  return createProductionEmailClient()
}

dev-email-client.ts

import nodemailer from 'nodemailer'
import type { Transporter } from 'nodemailer'
import type { EmailClient } from '@/lib/email/email-client-types'

// Email configuration
const emailConfig = {
  host: 'localhost',
  port: 1025,
  secure: false,
}

export function createDevEmailClient(): EmailClient {
  const transporter: Transporter = nodemailer.createTransport({
    host: emailConfig.host,
    port: emailConfig.port,
    secure: emailConfig.secure,
  })
  return {
    async sendEmail({ from, to, subject, content }) {
      await transporter.sendMail({
        from,
        to,
        subject,
        html: content,
      })
    },
  }
}

docker-compose.yml

version: "3.9"
services:
  mailpit:
    image: axllent/mailpit:latest
    container_name: dev-mailpit
    ports:
      - "1025:1025"   # SMTP
      - "8025:8025"   # Web UI
    # Add a small named volume if you want messages to survive container restarts
    volumes:
      - mailpit_data:/data
    environment:
      MP_DATABASE: /data/mailpit.db
volumes:
  mailpit_data:

email-client-types.ts

export interface EmailClient {
  sendEmail: (args: {
    from: string
    to: string
    subject: string
    content: string
    replyTo?: string
  }) => Promise<void>
}

email-sender.ts

const emailHTML = await renderSomeEmailHTML(data.otp)
const emailClient = createEmailClient(
  process.env.NODE_ENV as 'development' | 'production',
)
await emailClient.sendEmail({
  from: 'onboarding@example.com',
  to: data.email,
  subject: 'Here is your verification code',
  content: emailHTML,
})