PowerMTA Monitoring: Logs & Metrics That Matter
You can't improve what you don't measure. PowerMTA produces rich logs — here's what to watch so you catch deliverability problems before they spread.
TL;DR
Track delivery rate, bounces, deferrals, complaints and queue size. PowerMTA's CSV accounting logs hold all of it; a panel like AutoPMTA turns them into live dashboards.
PowerMTA accounting logs
PowerMTA writes detailed CSV accounting records for every delivery attempt — recipient, VMTA, result, response code and timing. These are the source of truth for analytics and debugging.
Metrics that matter
| Metric | Healthy range | Why it matters |
|---|---|---|
| Delivery rate | > 95% | Core inbox-reach signal |
| Hard bounce rate | < 2% | List quality |
| Complaint rate | < 0.1% | Content/consent quality |
| Deferral (4xx) rate | Low & stable | Throttling pressure |
More on each in our deliverability guide and complaint rate guide.
Queue health
A growing queue means mail isn't leaving fast enough — usually throttling or a misconfigured domain rule. Watch queue size per VMTA and per destination.
External monitoring
Pair internal logs with external signals: Google Postmaster Tools, Microsoft SNDS and blacklist checks via Spamhaus. Together they tell you how providers actually see you.
Alerting
Set thresholds: alert if bounce or complaint rates spike, if a VMTA lands on a blacklist, or if the queue balloons. Early alerts prevent small issues becoming reputation disasters.
AutoPMTA visualises PowerMTA logs, queue and reputation in real time. View plans.
Key takeaways
- PowerMTA's CSV accounting logs record every delivery attempt.
- Watch delivery, bounce, complaint and deferral rates.
- A growing queue signals throttling or misconfiguration.
- Combine internal logs with Postmaster Tools and SNDS.
Frequently asked questions
Where are PowerMTA logs stored?+
PowerMTA writes CSV accounting logs (and error/diagnostic logs) to its configured log directory on the server. Each record captures the recipient, VMTA, SMTP response and timing for every delivery attempt.
What is a good email delivery rate?+
A healthy delivery rate is above 95%. Combined with a hard bounce rate under 2% and complaint rate under 0.1%, it indicates strong list quality and sender reputation.
How do I monitor PowerMTA reputation?+
Combine PowerMTA's internal logs with external tools like Google Postmaster Tools, Microsoft SNDS and Spamhaus blacklist checks. A control panel like AutoPMTA centralises these signals.