SMTPQuotas

SMTPQuotas is a web app (with optional lightweight desktop agent) that monitors SMTP servers for the boring, business-killing failures: mailbox spool growth, disk/inode exhaustion, queue backlogs, rate-limit throttling, TLS cert expiry, DNSBL listings, and authentication errors. It connects via SSH/WinRM and reads MTA-specific signals (Postfix, Exim, Exchange, Haraka, etc.), normalizes them into a single health model, and sets practical alert thresholds based on historical baselines. The product focuses on “deliverability operations,” not marketing analytics: it tells admins what will break next week and exactly which knob to turn today. It includes runbook-style remediation guidance, alert routing to Slack/PagerDuty, and a simple “risk score” per server/domain. This is not a full APM suite; it’s narrow, opinionated monitoring for teams who run their own SMTP and keep getting surprised by queues, quotas, and blacklists.