Health Check

Monitor mailer health using @nestjs/terminus.

Setup

Install terminus:

pnpm add @nestjs/terminus

Usage

Inject MailerHealthIndicator in your health controller:

import { Controller, Get } from '@nestjs/common';
import { HealthCheck, HealthCheckService } from '@nestjs/terminus';
import { MailerHealthIndicator } from '@nestjs-modules/mailer';

@Controller('health')
export class HealthController {
  constructor(
    private health: HealthCheckService,
    private mailerHealth: MailerHealthIndicator,
  ) {}

  @Get()
  @HealthCheck()
  check() {
    return this.health.check([
      () => this.mailerHealth.isHealthy('mailer'),
    ]);
  }
}

Response

{
  "status": "ok",
  "info": {
    "mailer": {
      "status": "up",
      "transporters": "up"
    }
  }
}

With Queue

If MailerQueueModule is imported, the health check also reports queue metrics:

{
  "status": "ok",
  "info": {
    "mailer": {
      "status": "up",
      "transporters": "up",
      "queue": {
        "status": "up",
        "waiting": 3,
        "active": 1,
        "completed": 245,
        "failed": 2,
        "delayed": 0
      }
    }
  }
}

Custom Health Key

// Use a custom key for the health response
await this.mailerHealth.isHealthy('email-service');

tip

MailerHealthIndicator is automatically available when you import MailerModule. No additional configuration needed. It uses the existing verifyAllTransporters() method to check SMTP connectivity.