Email Delivery Monitoring: Making Sure Your Alerts Actually Arrive
The cruelest irony in monitoring is when your alerting channel fails silently. Email is the most common notification channel and the one most likely to have silent failures — spam filters, domain reputation issues, and provider outages all happen without any visible error.
AlertsDock sends you email alerts when services go down — but what monitors the monitor? Here is how to verify email delivery is working end-to-end.
The email delivery stack
Email delivery involves more steps than most engineers realize:
1. Your monitoring tool sends to an ESP (SendGrid, Mailgun, SES) 2. The ESP accepts and queues the message 3. The ESP attempts delivery to the recipient's MX server 4. The receiving server accepts or rejects 5. The mail client retrieves and displays
Failures can occur at any step — and most fail silently from the sender's perspective.
DMARC, SPF, and DKIM
Email deliverability starts with authentication records. Misconfigured DNS records cause legitimate monitoring emails to be silently rejected:
- SPF — specifies which servers are allowed to send email for your domain - DKIM — cryptographic signature verifying the message was not tampered - DMARC — policy for what to do when SPF/DKIM fails
Use a tool like MXToolbox to verify your records are correctly configured.
Monitoring email delivery with a heartbeat
Set up a canary test: send a test email every hour and verify receipt: ```bash # Cron job that sends test email and pings AlertsDock 0 * * * * send-test-email.sh && curl -fsS https://alertsdock.com/ping/{uuid} ```
If the ping doesn't arrive, your email pipeline is broken.
Backup notification channels
Never rely on a single notification channel. Configure at minimum: 1. Email (primary) 2. Slack or Discord (secondary) 3. Mobile push notification or SMS (for critical alerts)
AlertsDock supports all three. Set up escalation rules so critical monitors page you via all channels simultaneously.
Monitoring your email domain reputation
Poor sender reputation causes deliverability failures. Watch: - Bounce rate (keep below 2%) - Spam complaint rate (keep below 0.1%) - Blacklist status (check MXToolbox weekly)
Feature Guide
Uptime Monitoring
AlertsDock gives teams uptime monitoring for websites, APIs, TCP checks, DNS checks, SSL expiry, and fast alert routing without enterprise overhead.
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