Verify email deliverability for free

This is an example docker-compose.yml running Reacher service on DigitalOcean to verify email deliverability. Port 22 muse be open

services:
  rabbitmq:
    image: rabbitmq:4.0-management
    environment:
      RABBITMQ_DEFAULT_USER: reacher
      RABBITMQ_DEFAULT_PASS: reacher
    ports:
      - "5672:5672"
      - "15672:15672"
    restart: unless-stopped
    networks:
      - dokploy-network
    healthcheck:
      test: ["CMD", "rabbitmq-diagnostics", "ping"]
      interval: 5s
      timeout: 3s
      retries: 5

  worker:
    image: reacherhq/backend:v0.11.5
    ports:
      - "8080:8080"
    depends_on:
      rabbitmq:
        condition: service_healthy
    environment:
      RCH__BACKEND_NAME: worker
      RCH__HTTP_PORT: ${RCH__HTTP_PORT}
      RCH__HELLO_NAME: ${RCH__HELLO_NAME}
      RCH__FROM_EMAIL: ${RCH__FROM_EMAIL}
      RCH__HEADER_SECRET: ${RCH__HEADER_SECRET}
      RUST_LOG: reacher=info
      RCH__WORKER__ENABLE: true
      RCH__WORKER__RABBITMQ__URL: amqp://reacher:reacher@rabbitmq:5672
      RCH__STORAGE__POSTGRES__DB_URL: ${RCH__DB_URL}
      RCH__WORKER__THROTTLE__MAX_REQUESTS_PER_DAY: ${RCH__WORKER__THROTTLE__MAX_REQUESTS_PER_DAY}
    restart: unless-stopped
    networks:
      - dokploy-network

networks:
  dokploy-network:
    external: true

Env:

RCH__HTTP_PORT=8080
RCH__HELLO_NAME=verify.example.com
RCH__FROM_EMAIL=hello@verify.example.com
RCH__HEADER_SECRET=LONGSTRINGOFWHATEVR
RCH__WORKER__THROTTLE__MAX_REQUESTS_PER_DAY=1000000
RCH__DB_URL=postgresql://yourdb

Then to verify:

type EmailVerificationResponse = {
  input: string,
  is_reachable: 'safe' | 'risky' | 'unknown' | 'invalid',
  misc: MiscInfo,
  mx: MxInfo,
  smtp: SmtpInfo,
  syntax: SyntaxInfo,
};

const ACCEPTED_STATUSES = ['safe', 'risky'];
const TIMEOUT = 1000 * 5;
export const validateEmail = async (email: string) => {
  if (!email.includes('@')) return false;

  try {
    const response = await request<EmailVerificationResponse>({
      url: 'https://verify.example.com/v0/check_email',
      method: 'post',
      data: { to_email: email },
      headers: { 'x-reacher-secret': process.env.REACHER_TOKEN! },
      timeout: TIMEOUT,
    });

    return ACCEPTED_STATUSES.includes(response.is_reachable);
  } catch {
    return false;
  }
};