Uptime Monitoring as a Service: NestJS Cron Jobs, Twilio Alerts, and Status Pages

Every minute of downtime costs money. SiteGuard checks endpoints every 60 seconds and alerts teams before customers notice.

1. NestJS Scheduled Monitoring

The scheduler runs parallel HTTP probes against all monitored endpoints:

typescript
@Injectable()
export class MonitorService {
  @Cron(CronExpression.EVERY_MINUTE)
  async checkEndpoints() {
    const endpoints = await this.redis.smembers('monitored_urls');
    const results = await Promise.allSettled(
      endpoints.map(url => this.httpService.get(url, { timeout: 10000 }).toPromise())
    );
    results.forEach((result, i) => {
      if (result.status === 'rejected') this.alertService.triggerAlert(endpoints[i]);
    });
  }
}

2. Multi-Channel Alerts

When downtime is detected, alerts fire simultaneously via Twilio SMS, Slack webhooks, and SendGrid email — ensuring someone always gets notified.

3. Public Status Pages

Each customer gets a branded status page showing uptime history, response times, and incident reports.

Summary

Scheduled probes + multi-channel alerts + public status pages create a monitoring service that catches downtime within 60 seconds.